[X86][SSE] Vector integer/float conversion memory folding

Tidied up some entries in the folding tables so that they are under the correct comment section (they were categorised as AVX2 instructions when they're AVX1).

Minor patch agreed with qcolombet.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220613 91177308-0d34-0410-b5e6-96231b3b80d8