vpx_dsp: get32x32var_avx2() cleanup
vpx_dsp: get32x32var_avx2() cleanup

renamed to get32x16var_avx2()

BUG=webm:1404

Change-Id: Icb8f3986c9c9c646e13a69430db7235fc7e1a036

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