pass 'win64' instead of 'x64' to the assembler
pass 'win64' instead of 'x64' to the assembler

nasm does not accept x64

yasm has accepted (and appears to prefer) win64 at least as far back as
1.0.0:
http://yasm.tortall.net/releases/Release1.0.0.html

Change-Id: Ied881b1df0570da256b1bd7e131e7817e47f768f

ShiftMediaProject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx