Fix a signed shift overflow in vpx_rb_read_inv_signed_literal.
Fix a signed shift overflow in vpx_rb_read_inv_signed_literal.

Found with clang -fsanitize=integer

Change-Id: I17cb2166c06ff463abfaf9b0e6bc749d0d6fdf94

mwgoldsmith/vpx,jmvalin/aom,smarter/aom,luctrudeau/aom,openpeer/libvpx_new,openpeer/libvpx_new,ShiftMediaProject/libvpx,ittiamvpx/libvpx-1,luctrudeau/aom,jmvalin/aom,smarter/aom,webmproject/libvpx,jmvalin/aom,webmproject/libvpx,ittiamvpx/libvpx-1,Topopiccione/libvpx,Topopiccione/libvpx,ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,mbebenita/aom,luctrudeau/aom,mbebenita/aom,mwgoldsmith/vpx,openpeer/libvpx_new,mwgoldsmith/vpx,shacklettbp/aom,openpeer/libvpx_new,Topopiccione/libvpx,thdav/aom,thdav/aom,mbebenita/aom,smarter/aom,mwgoldsmith/libvpx,shacklettbp/aom,webmproject/libvpx,luctrudeau/aom,GrokImageCompression/aom,webmproject/libvpx,GrokImageCompression/aom,GrokImageCompression/aom,shacklettbp/aom,ittiamvpx/libvpx-1,shacklettbp/aom,jmvalin/aom,mwgoldsmith/libvpx,mwgoldsmith/libvpx,GrokImageCompression/aom,shacklettbp/aom,Topopiccione/libvpx,GrokImageCompression/aom,mbebenita/aom,Topopiccione/libvpx,mbebenita/aom,smarter/aom,mwgoldsmith/libvpx,mwgoldsmith/vpx,mbebenita/aom,openpeer/libvpx_new,mbebenita/aom,jmvalin/aom,ittiamvpx/libvpx-1,ittiamvpx/libvpx-1,GrokImageCompression/aom,smarter/aom,Topopiccione/libvpx,mwgoldsmith/vpx,mwgoldsmith/libvpx,mwgoldsmith/vpx,webmproject/libvpx,openpeer/libvpx_new,ShiftMediaProject/libvpx,mbebenita/aom,ShiftMediaProject/libvpx,shacklettbp/aom,jmvalin/aom,ittiamvpx/libvpx-1,mwgoldsmith/libvpx,thdav/aom,thdav/aom,smarter/aom,mbebenita/aom,thdav/aom,luctrudeau/aom,thdav/aom,luctrudeau/aom