perf/amd/uncore: Allow the driver to be built as a module

Add support to build the AMD uncore driver as a module.

This is in order to facilitate development without having
to reboot the kernel in most cases.

Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210817221048.88063-8-kim.phillips@amd.com