Support -mevex512 for AVX512FP16 intrins

gcc/ChangeLog:

	* config/i386/sse.md (V48H_AVX512VL): Add TARGET_EVEX512.
	(VFH): Ditto.
	(VF2H): Ditto.
	(VFH_AVX512VL): Ditto.
	(VHFBF): Ditto.
	(VHF_AVX512VL): Ditto.
	(VI2H_AVX512VL): Ditto.
	(VI2F_256_512): Ditto.
	(VF48_I1248): Remove unused iterator.
	(VF48H_AVX512VL): Add TARGET_EVEX512.
	(VF_AVX512): Remove unused iterator.
	(REDUC_PLUS_MODE): Add TARGET_EVEX512.
	(REDUC_SMINMAX_MODE): Ditto.
	(FMAMODEM): Ditto.
	(VFH_SF_AVX512VL): Ditto.
	(VEC_PERM_AVX2): Ditto.

Co-authored-by: Hu, Lin1 <lin1.hu@intel.com>