[llvm] [NFC][AMDGPU] Convert amdpal.ll to autogenerated CHECK lines (PR #141026)

[Harrison Hao via llvm-commits]

harrisonGPU wrote:

> > Okay, can I add these Metadata check after using update_llc_test_checks.py? Because I have a patch will chang this lit test, so I updated it.
> 
> The next time someone runs it, the checks will be lost again. There isn't that much in this test, you can probably just manually do it?

 I think mcpu is tahiti or tonga, may be we can update it? Because I know these are old architecture.

https://github.com/llvm/llvm-project/pull/141026