[llvm] [AMDGPU][SIInsertWaitcnts][NFC] Move static array definition (PR #178014)

[via llvm-commits]

================
@@ -349,7 +349,8 @@ class WaitcntGenerator {
   const AMDGPU::HardwareLimits *Limits = nullptr;
 
 public:
-  WaitcntGenerator() = default;
+  WaitcntGenerator() = delete;
----------------
vporpo wrote:

Yes this is unrelated, it's a follow-up to the previous patch that allowed us to drop the default constructors, I should have uploaded it as a separate patch, my bad.
We don't really need to delete it, but it just makes explicit that we disabled default construction on purpose.

https://github.com/llvm/llvm-project/pull/178014