Add AVX-512 and related features to the CPUID detection code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188745 91177308-0d34-0410-b5e6-96231b3b80d8
Fix formatting. No functional change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188746 91177308-0d34-0410-b5e6-96231b3b80d8