sse.md (vec_unpacks_lo_<mode>, [...]): Change VI124_128 mode to VI124_AVX2.

	* config/i386/sse.md (vec_unpacks_lo_<mode>,
	vec_unpacks_hi_<mode>, vec_unpacku_lo_<mode>,
	vec_unpacku_hi_<mode>): Change VI124_128 mode to
	VI124_AVX2.
	* config/i386/i386.c (ix86_expand_sse_unpack): Handle
	V32QImode, V16HImode and V8SImode for TARGET_AVX2.

From-SVN: r179872