[AVX512] Bring vmovq instructions names into alignment with the AVX and SSE...

[AVX512] Bring vmovq instructions names into alignment with the AVX and SSE names. Add a missing encoding to disassembler and assembler.

I believe this also fixes a case where a 64-bit memory form that is documented as being unsupported in 32-bit mode was able to be selected there.

llvm-svn: 256483