[llvm] AMDGPU: Add target feature for aligned VGPR requirement (PR #155336)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> I do not like it too, and probably this is not the only place we have to check it. But that's right, this is the right thing to do.

I'm adding more. Plus the assembler really should too, it's checking the same instruction feature 

https://github.com/llvm/llvm-project/pull/155336