decodemv cleanup/improvements
decodemv cleanup/improvements

Removed unnecessary variables, unrolled functions, eliminated
unnecessary mv bounds checks and branches.

Change-Id: I02d034c70cd97b65025d59dd67c695e1db529f0b

abwiz0086/webm.libvpx,Suvarna1488/webm.libvpx,reimaginemedia/webm.libvpx,Maria1099/webm.libvpx,kalli123/webm.libvpx,Suvarna1488/webm.libvpx,jdm/libvpx,jacklicn/webm.libvpx,cinema6/libvpx,ShiftMediaProject/libvpx,felipebetancur/libvpx,luctrudeau/aom,liqianggao/libvpx,ittiamvpx/libvpx-1,stewnorriss/libvpx,charup/https---github.com-webmproject-libvpx-,Distrotech/libvpx,Distrotech/libvpx,gshORTON/webm.libvpx,liqianggao/libvpx,turbulenz/libvpx,Topopiccione/libvpx,Topopiccione/libvpx,Maria1099/webm.libvpx,reimaginemedia/webm.libvpx,thdav/aom,thdav/aom,matanbs/webm.libvpx,cinema6/libvpx,cinema6/libvpx,shareefalis/libvpx,Acidburn0zzz/webm.libvpx,zofuthan/libvpx,kim42083/webm.libvpx,n4t/libvpx,goodleixiao/vpx,ittiamvpx/libvpx-1,iniwf/webm.libvpx,jdm/libvpx,GrokImageCompression/aom,n4t/libvpx,goodleixiao/vpx,GrokImageCompression/aom,ittiamvpx/libvpx-1,smarter/aom,Laknot/libvpx,Maria1099/webm.libvpx,ittiamvpx/libvpx,stewnorriss/libvpx,running770/libvpx,sanyaade-teachings/libvpx,matanbs/webm.libvpx,thdav/aom,shacklettbp/aom,luctrudeau/aom,zofuthan/libvpx,mwgoldsmith/vpx,charup/https---github.com-webmproject-libvpx-,smarter/aom,running770/libvpx,Distrotech/libvpx,mbebenita/aom,kim42083/webm.libvpx,hsueceumd/test_hui,Laknot/libvpx,altogother/webm.libvpx,running770/libvpx,felipebetancur/libvpx,abwiz0086/webm.libvpx,shyamalschandra/libvpx,kalli123/webm.libvpx,shacklettbp/aom,pcwalton/libvpx,altogother/webm.libvpx,kalli123/webm.libvpx,openpeer/libvpx_new,mbebenita/aom,shacklettbp/aom,ittiamvpx/libvpx-1,gshORTON/webm.libvpx,luctrudeau/aom,n4t/libvpx,openpeer/libvpx_new,jmvalin/aom,running770/libvpx,goodleixiao/vpx,stewnorriss/libvpx,kleopatra999/webm.libvpx,shareefalis/libvpx,shyamalschandra/libvpx,matanbs/vp982,openpeer/libvpx_new,ShiftMediaProject/libvpx,GrokImageCompression/aom,turbulenz/libvpx,shareefalis/libvpx,lyx2014/libvpx_c,turbulenz/libvpx,Laknot/libvpx,shyamalschandra/libvpx,jdm/libvpx,thdav/aom,VTCSecureLLC/libvpx,shyamalschandra/libvpx,matanbs/webm.libvpx,smarter/aom,felipebetancur/libvpx,shyamalschandra/libvpx,lyx2014/libvpx_c,WebRTC-Labs/libvpx,mbebenita/aom,goodleixiao/vpx,kalli123/webm.libvpx,mbebenita/aom,vasilvv/esvp8,kim42083/webm.libvpx,hsueceumd/test_hui,hsueceumd/test_hui,VTCSecureLLC/libvpx,iniwf/webm.libvpx,Topopiccione/libvpx,gshORTON/webm.libvpx,matanbs/vp982,mbebenita/aom,kleopatra999/webm.libvpx,jacklicn/webm.libvpx,kleopatra999/webm.libvpx,iniwf/webm.libvpx,jacklicn/webm.libvpx,zofuthan/libvpx,gshORTON/webm.libvpx,thdav/aom,felipebetancur/libvpx,felipebetancur/libvpx,zofuthan/libvpx,ittiamvpx/libvpx-1,matanbs/vp982,jmvalin/aom,webmproject/libvpx,lyx2014/libvpx_c,matanbs/webm.libvpx,Topopiccione/libvpx,hsueceumd/test_hui,turbulenz/libvpx,openpeer/libvpx_new,goodleixiao/vpx,kim42083/webm.libvpx,Suvarna1488/webm.libvpx,shyamalschandra/libvpx,mwgoldsmith/vpx,shareefalis/libvpx,vasilvv/esvp8,VTCSecureLLC/libvpx,ShiftMediaProject/libvpx,vasilvv/esvp8,Acidburn0zzz/webm.libvpx,sanyaade-teachings/libvpx,vasilvv/esvp8,pcwalton/libvpx,webmproject/libvpx,matanbs/vp982,kalli123/webm.libvpx,iniwf/webm.libvpx,Topopiccione/libvpx,reimaginemedia/webm.libvpx,kleopatra999/webm.libvpx,jmvalin/aom,stewnorriss/libvpx,mbebenita/aom,charup/https---github.com-webmproject-libvpx-,altogother/webm.libvpx,Maria1099/webm.libvpx,kleopatra999/webm.libvpx,lyx2014/libvpx_c,stewnorriss/libvpx,jacklicn/webm.libvpx,gshORTON/webm.libvpx,hsueceumd/test_hui,zofuthan/libvpx,Distrotech/libvpx,webmproject/libvpx,Acidburn0zzz/webm.libvpx,Topopiccione/libvpx,kim42083/webm.libvpx,liqianggao/libvpx,abwiz0086/webm.libvpx,reimaginemedia/webm.libvpx,VTCSecureLLC/libvpx,cinema6/libvpx,jdm/libvpx,ittiamvpx/libvpx-1,kalli123/webm.libvpx,Laknot/libvpx,mwgoldsmith/vpx,thdav/aom,ittiamvpx/libvpx,jmvalin/aom,pcwalton/libvpx,mbebenita/aom,mwgoldsmith/vpx,abwiz0086/webm.libvpx,smarter/aom,mwgoldsmith/libvpx,altogother/webm.libvpx,reimaginemedia/webm.libvpx,luctrudeau/aom,shacklettbp/aom,smarter/aom,jmvalin/aom,matanbs/vp982,GrokImageCompression/aom,goodleixiao/vpx,mbebenita/aom,vasilvv/esvp8,webmproject/libvpx,GrokImageCompression/aom,cinema6/libvpx,jdm/libvpx,shacklettbp/aom,Maria1099/webm.libvpx,pcwalton/libvpx,Acidburn0zzz/webm.libvpx,running770/libvpx,cinema6/libvpx,matanbs/webm.libvpx,GrokImageCompression/aom,turbulenz/libvpx,altogother/webm.libvpx,abwiz0086/webm.libvpx,vasilvv/esvp8,jacklicn/webm.libvpx,ShiftMediaProject/libvpx,Maria1099/webm.libvpx,WebRTC-Labs/libvpx,mwgoldsmith/libvpx,sanyaade-teachings/libvpx,hsueceumd/test_hui,VTCSecureLLC/libvpx,iniwf/webm.libvpx,felipebetancur/libvpx,luctrudeau/aom,n4t/libvpx,charup/https---github.com-webmproject-libvpx-,VTCSecureLLC/libvpx,WebRTC-Labs/libvpx,shareefalis/libvpx,luctrudeau/aom,mwgoldsmith/libvpx,mbebenita/aom,turbulenz/libvpx,jdm/libvpx,ittiamvpx/libvpx,Suvarna1488/webm.libvpx,Laknot/libvpx,WebRTC-Labs/libvpx,mwgoldsmith/libvpx,iniwf/webm.libvpx,sanyaade-teachings/libvpx,liqianggao/libvpx,Acidburn0zzz/webm.libvpx,pcwalton/libvpx,liqianggao/libvpx,charup/https---github.com-webmproject-libvpx-,altogother/webm.libvpx,mwgoldsmith/libvpx,lyx2014/libvpx_c,matanbs/vp982,stewnorriss/libvpx,abwiz0086/webm.libvpx,webmproject/libvpx,mwgoldsmith/vpx,turbulenz/libvpx,shareefalis/libvpx,openpeer/libvpx_new,ShiftMediaProject/libvpx,sanyaade-teachings/libvpx,kim42083/webm.libvpx,openpeer/libvpx_new,matanbs/webm.libvpx,mwgoldsmith/libvpx,Distrotech/libvpx,kleopatra999/webm.libvpx,liqianggao/libvpx,Laknot/libvpx,shacklettbp/aom,Distrotech/libvpx,n4t/libvpx,gshORTON/webm.libvpx,matanbs/vp982,jacklicn/webm.libvpx,vasilvv/esvp8,jmvalin/aom,running770/libvpx,Suvarna1488/webm.libvpx,Acidburn0zzz/webm.libvpx,ittiamvpx/libvpx,turbulenz/libvpx,mwgoldsmith/vpx,cinema6/libvpx,pcwalton/libvpx,reimaginemedia/webm.libvpx,smarter/aom,Suvarna1488/webm.libvpx,lyx2014/libvpx_c,zofuthan/libvpx,webmproject/libvpx,ittiamvpx/libvpx,ittiamvpx/libvpx,turbulenz/libvpx,charup/https---github.com-webmproject-libvpx-,WebRTC-Labs/libvpx