[libc] Remove CPU dependent AMDGPU instructions (#80707)

Summary:
Some recent changes allowed us to remove target level divergence one
these instructions. This patch removes the wavefront dependent
divergence for the ballot and thread ID functions, as well as the clock.
The changes to the "Vendor" library simply disables target specific
optimizations in the implementation. This should be removed in its
entirety when the LLVM `libm` is sufficiently implemented.

The remaining areas of divergence is only the RPC packet size and the
fixed frequency counter.