vp9_decodeframe: simplify init_read_bit_buffer signature
vp9_decodeframe: simplify init_read_bit_buffer signature

Change-Id: I342075eb5a4ba2a85d36d47ae52d1f3476039e31

luctrudeau/aom,mwgoldsmith/vpx,shacklettbp/aom,mwgoldsmith/vpx,stewnorriss/libvpx,thdav/aom,felipebetancur/libvpx,goodleixiao/vpx,goodleixiao/vpx,VTCSecureLLC/libvpx,shyamalschandra/libvpx,luctrudeau/aom,stewnorriss/libvpx,jmvalin/aom,running770/libvpx,openpeer/libvpx_new,ittiamvpx/libvpx-1,mwgoldsmith/libvpx,ittiamvpx/libvpx-1,mbebenita/aom,Topopiccione/libvpx,mbebenita/aom,GrokImageCompression/aom,zofuthan/libvpx,jmvalin/aom,VTCSecureLLC/libvpx,smarter/aom,goodleixiao/vpx,zofuthan/libvpx,goodleixiao/vpx,liqianggao/libvpx,thdav/aom,mbebenita/aom,GrokImageCompression/aom,thdav/aom,liqianggao/libvpx,running770/libvpx,openpeer/libvpx_new,mbebenita/aom,smarter/aom,mwgoldsmith/vpx,ittiamvpx/libvpx-1,ShiftMediaProject/libvpx,felipebetancur/libvpx,stewnorriss/libvpx,ShiftMediaProject/libvpx,openpeer/libvpx_new,jmvalin/aom,zofuthan/libvpx,mwgoldsmith/vpx,shyamalschandra/libvpx,luctrudeau/aom,shacklettbp/aom,ShiftMediaProject/libvpx,Topopiccione/libvpx,shyamalschandra/libvpx,GrokImageCompression/aom,VTCSecureLLC/libvpx,liqianggao/libvpx,luctrudeau/aom,mwgoldsmith/vpx,thdav/aom,mwgoldsmith/libvpx,mwgoldsmith/libvpx,liqianggao/libvpx,Topopiccione/libvpx,openpeer/libvpx_new,Topopiccione/libvpx,VTCSecureLLC/libvpx,luctrudeau/aom,running770/libvpx,shacklettbp/aom,goodleixiao/vpx,GrokImageCompression/aom,mwgoldsmith/libvpx,felipebetancur/libvpx,ittiamvpx/libvpx-1,liqianggao/libvpx,mbebenita/aom,jmvalin/aom,Topopiccione/libvpx,shacklettbp/aom,Topopiccione/libvpx,GrokImageCompression/aom,zofuthan/libvpx,mbebenita/aom,smarter/aom,mwgoldsmith/libvpx,jmvalin/aom,zofuthan/libvpx,webmproject/libvpx,zofuthan/libvpx,thdav/aom,smarter/aom,ittiamvpx/libvpx-1,running770/libvpx,mbebenita/aom,running770/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,VTCSecureLLC/libvpx,shyamalschandra/libvpx,mwgoldsmith/vpx,jmvalin/aom,ittiamvpx/libvpx-1,webmproject/libvpx,felipebetancur/libvpx,stewnorriss/libvpx,smarter/aom,mbebenita/aom,goodleixiao/vpx,stewnorriss/libvpx,luctrudeau/aom,webmproject/libvpx,thdav/aom,shyamalschandra/libvpx,running770/libvpx,stewnorriss/libvpx,shacklettbp/aom,webmproject/libvpx,shyamalschandra/libvpx,felipebetancur/libvpx,openpeer/libvpx_new,shacklettbp/aom,mwgoldsmith/libvpx,mbebenita/aom,VTCSecureLLC/libvpx,GrokImageCompression/aom,felipebetancur/libvpx,ShiftMediaProject/libvpx,smarter/aom,openpeer/libvpx_new,webmproject/libvpx,liqianggao/libvpx