[CUDA][HIP] Always defer diagnostics for wrong-sided reference

When a device function calls a host function or vice versa, this is wrong-sided
reference. Currently clang immediately diagnose it. This is different from nvcc
behavior, where it is diagnosed only if the function is really emitted.

Current clang behavior causes false alarms for valid use cases.

This patch let clang always defer diagnostics for wrong-sided
reference.

Differential Revision: https://reviews.llvm.org/D83893