[llvm] [NVPTX] restrict `cvta.param` use to kernels only. (PR #112278)

[Artem Belevich via llvm-commits]

Artem-B wrote:

For the context: https://godbolt.org/z/xv8YGad9n

If compiled with recent clang for `sm_89`, `cvta.param` instruction in `f0` produces invalid pointer.

https://github.com/llvm/llvm-project/pull/112278