[llvm] [AMDGPU][SDAG] Support source modifiers on select integer operands (PR #147325)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> Thanks to all reviewers but I think I need to deprecate this PR in favour of the simpler #149110.

On average it's probably better to do it that way. However, we don't have any of the combines trying to make the form match for integers. So on this path, there's additional work to actively try to form this 

https://github.com/llvm/llvm-project/pull/147325