[llvm] [NFC][AMDGPU] clang-format `llvm/lib/Target/AMDGPU/SIISelLowering.cpp` (PR #112645)

[Shilei Tian via llvm-commits]

shiltian wrote:

This is a pretty intrusive change. I can understand the reason if we don't want to do it, but the format of some code is really off.

https://github.com/llvm/llvm-project/pull/112645