[mlir] Fix definition of type traits struct member for some ops (#192047)
This commit fixes all appearences of `numLowBitsAvailable` to the
correct `NumLowBitsAvailable`. Prior to this change, instantiation of
templates like `llvm::PointerIntPair<mlir::ModuleOp, 3>` would not
compile.
See usage of `NumLowBitsAvailable`:
https://github.com/llvm/llvm-project/blob/224c429e858f8171852990a6f7b2b3590eeaffb7/llvm/include/llvm/ADT/PointerIntPair.h#L169