perf/x86/amd/power: Assign pmu.module

Assign pmu.module so the driver can't be unloaded whilst in use.

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/20210817221048.88063-4-kim.phillips@amd.com