vp9_decodframe.c: use vpx_memset instead of cast
vp9_decodframe.c: use vpx_memset instead of cast

Fix warning with -Wstrict-aliasing=1

Change-Id: Idfac09be1ab328923883e63436577f1018c895b8

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