[llvm] [AMDGPU][GlobalISel] Enable kernel argument preloading (PR #134655)

[Tim Gymnich via llvm-commits]

tgymnich wrote:

@kerbowa could you please have another look. Hidden arguments are now handled and the code paths for SDAG and GISel are now mostly the same.

https://github.com/llvm/llvm-project/pull/134655