[MLIR][GPU] Make the path to ROCm a runtime option

Our current build assumes that the path to ROCm we find at build time
will be the path at which ROCm is located when the built code is
executed. This commit adds a --rocm-path option to SerializeToHsaco,
and removes the HIP dependency that the SerializeToHsaco previously had.

Depends on D114113

(though the dependency is to ensure the diffs apply cleanly and to capture the dependency on D114107)

Reviewed By: mehdi_amini

Differential Revision: https://reviews.llvm.org/D114114