vp9_decodeframe.h: remove unused prototype
vp9_decodeframe.h: remove unused prototype

vp9_init_dequantizer() was deleted in:
bdd249b Optimize the dequantization process on decoder side.

Change-Id: Iedb5b6a3a03964dd6901c1e3b2325194d94bc708

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