[hip] Revise `GlobalDecl` constructors. NFC.

Summary:
- https://reviews.llvm.org/D68578 revises the `GlobalDecl` constructors
  to ensure all GPU kernels have `ReferenceKenelKind` initialized
  properly with an explicit constructor and static one. But, there are
  lots of places using the implicit constructor triggering the assertion
  on non-GPU kernels. That's found in compilation of many tests and
  workloads.
- Fixing all of them may change more code and, more importantly, all of
  them assumes the default kernel reference kind. This patch changes
  that constructor to tell `CUDAGlobalAttr` and construct `GlobalDecl`
  properly.

Reviewers: yaxunl

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D76344