[llvm] [SelectionDAG] Remove LegalTypes argument from getShiftAmountConstant. (PR #97653)

[Craig Topper via llvm-commits]

topperc wrote:

https://github.com/llvm/llvm-project/pull/97645 has landed so this flag no longer does anything. The patch itself is just a mechanical code update. I only posted for review to stage the changes.

https://github.com/llvm/llvm-project/pull/97653