[x86] Put 'C' after 'i' on all the AVX-512 intrisics that take const ints. 'C' is a suffix modifier not a prefix modififier. Also put 'C' on the pointers in all of the gather instrinsics. I think they previously had one due to the misordering. I'm still thinking the 'iC' actually need to be a 'Ii' since they really require an ICE.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@224913 91177308-0d34-0410-b5e6-96231b3b80d8