[llvm] Fix parentheses for clarity in X86ISelLowering.cpp (PR #121954)

[via llvm-commits]

soumyaGhoshh wrote:

by the way while cloning my forked repo, will shallow cloning affect the merging with upstream repo in any way ? cause i tried cloning and it repeatedly failed for like 5 times on stages 

https://github.com/llvm/llvm-project/pull/121954