[x86][icelake][gfni]

added gfni feature recognition
added intrinsics support for gfni instructions
  _mm_gf2p8affineinv_epi64_epi8
  _mm_mask_gf2p8affineinv_epi64_epi8
  _mm_maskz_gf2p8affineinv_epi64_epi8
  _mm256_gf2p8affineinv_epi64_epi8
  _mm256_mask_gf2p8affineinv_epi64_epi8
  _mm256_maskz_gf2p8affineinv_epi64_epi8
  _mm512_gf2p8affineinv_epi64_epi8
  _mm512_mask_gf2p8affineinv_epi64_epi8
  _mm512_maskz_gf2p8affineinv_epi64_epi8
  _mm_gf2p8affine_epi64_epi8
  _mm_mask_gf2p8affine_epi64_epi8
  _mm_maskz_gf2p8affine_epi64_epi8
  _mm256_gf2p8affine_epi64_epi8
  _mm256_mask_gf2p8affine_epi64_epi8
  _mm256_maskz_gf2p8affine_epi64_epi8
  _mm512_gf2p8affine_epi64_epi8
  _mm512_mask_gf2p8affine_epi64_epi8
  _mm512_maskz_gf2p8affine_epi64_epi8
  _mm_gf2p8mul_epi8
  _mm_mask_gf2p8mul_epi8
  _mm_maskz_gf2p8mul_epi8
  _mm256_gf2p8mul_epi8
  _mm256_mask_gf2p8mul_epi8
  _mm256_maskz_gf2p8mul_epi8
  _mm512_gf2p8mul_epi8
  _mm512_mask_gf2p8mul_epi8
  _mm512_maskz_gf2p8mul_epi8
matching a similar work on the backend (D40373)
Differential Revision: https://reviews.llvm.org/D41582


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@321477 91177308-0d34-0410-b5e6-96231b3b80d8