x86: adjust MOVSD attributes

x86: adjust MOVSD attributes

The non-SSE2AVX form of the SIMD variant of the instruction needlessly
has the (still multi-purpose) IgnoreSize attribute. All other similar
SSE2 insns use NoRex64 instead. Make this consistent, noting that the
SSE2AVX form can't have the same change made - there the memory operand
doesn't at the same time permit RegXMM (which logic uses when deciding
whether a Q suffix is okay outside of 64-bit mode).