[llvm] Fix warnings while compiling SLPVectorizer.cpp (PR #118051)

[Anutosh Bhat via llvm-commits]

anutosh491 wrote:

cc @alexey-bataev 

I think you approved this last week but hasn't been merged yet. 
I think this might ready. Could you considering merging if nothing is left to be addressed ?

https://github.com/llvm/llvm-project/pull/118051