quantize: add untested function
quantize: add untested function

vp9_quantize_fp_sse2 was only tested in non-hbd
configuration. Missed when fixing this for
vpx_quantize_b_sse2.

Change-Id: Ide346e5727d74281c774f605c90d280050e0bf62

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