[llvm] [AMDGPU][GlobalISel] Fix load/store of pointer vectors, buffer.*.pN (PR #110714)

[NAKAMURA Takumi via llvm-commits]

chapuni wrote:

Excuse me, I've reverted this. For example, https://lab.llvm.org/buildbot/#/builders/63/builds/1865

https://github.com/llvm/llvm-project/pull/110714