[llvm] [AMDGPU] Add MC support for new gfx1250 src_flat_scratch_base_lo/hi (PR #152203)

[Stanislav Mekhanoshin via llvm-commits]

rampitec wrote:

> ⚠️ C/C++ code formatter, clang-format found issues in your code. ⚠️
> You can test this locally with the following command:
> 
> View the diff from clang-format here.

I am going to ignore this one, all formatting around is like that.

https://github.com/llvm/llvm-project/pull/152203