[llvm] AMDGPU: Use "countMaxActiveBits() <= 5" to define uint5Bits (PR #115543)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> > I think the whole original patch should be reverted
> 
> What is the original patch? WE should not do pattern match for x << (32 -y) >> (32 - y) to bfe x, 0, y?

Yes

https://github.com/llvm/llvm-project/pull/115543