[PATCH] x86: Remove the restriction for size of the mask register in AVX10

[Jiang, Haochen]

> Well, if no template uses it anymore, then the attribute can hardly still
> be needed for anything. From my checking, all other affected templates
> are restricted based on their EVex<N> attributes instead. And my
> recollection also is that I introduced the attribute solely for the
> purpose of the opmask insns.

I suppose we could remove that if that is the case and I am finding a proper
way since we need to keep some diagnostic messages for the options.

Thx,
Haochen

> 
> Yet of course if internally you have indications that the attribute is
> going to be needed for something again (within foreseeable future), then
> we might better keep it.
> 
> Jan