amd/common: Move ac_export_mrt_z to ac_llvm_build.

The aim of this commit is to keep ac_shader_util LLVM-free,
since we would like to use it in ACO later.

Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
4 files changed