AVX512: Fix predicate of AVX pcmpeqw/b , pcmpgtb/w/d instructions . AVX512...

AVX512: Fix predicate of AVX pcmpeqw/b , pcmpgtb/w/d instructions . AVX512 version of this instructions return result in kmask register, so AVX patterns should not be disabled.

Differential Revision: http://reviews.llvm.org/D17517

llvm-svn: 261619