[llvm] [AMDGPU] Change the immediate operand of s_waitcnt_depctr / s_wait_alu (PR #169378)

[Jay Foad via llvm-commits]

jayfoad wrote:

> > While it's probably fine if they are 0 they have always been set, so we need to double check there aren't any unintended consequences of not setting them.
> 
> I can run some testing on real hardware to smoke out any unintended consequences.

I have run Vulkan CTS testing on Navi31 + Navi33 + Navi48 with no failures. Is that good enough?

https://github.com/llvm/llvm-project/pull/169378