Fix mmx / sse2 / ssse3 build

We never want the mmx bits, since we depend on x86-64 as a floor which
always has sse2.  We do want the sse2 bits always and we want the ssse3
bits when supported.

Change-Id: Ie5a51834f85529d714741c901f2f71b7c9b19511
2 files changed