Refactor mode iterator V_128 and V_128H, V_256 and V_256H

Refactor mode iterator V_128 and V_128H, V_256 and V_256H

Merge then together.

gcc/ChangeLog:

	* config/i386/sse.md (vec_set<mode>): Removed.
	(V_128H): Merge into ..
	(V_128): .. this.
	(V_256H): Merge into ..
	(V_256): .. this.
	(V_512): Add V32HF, V32BF.
	(*ssse3_palignr<mode>_perm): Adjust mode iterator from V_128H
	to V_128.
	(vcond<mode><sseintvecmodelower>): Removed
	(vcondu<mode><sseintvecmodelower>): Removed.
	(avx_vbroadcastf128_<mode>): Refator from V_256H to V_256.