The AMDGPU backend uses a pass to transform calls to the `printf`
function to a built-in verision for either HIP or OpenCL. Currently this
does not respect `-fno-builtin` and is always emitted. This allows the
user to turn off this functionality as is standard for these types of
built-in transformations. The motivation behind this change is to allow
the `libc` project to provide a linkable version of the `printf`
function in the future.
Reviewed By: sameerds
Differential Revision: https://reviews.llvm.org/D158477
