perf/arm_pmu_platform: Fix error handling

If we're aborting after failing to register the PMU device,
we probably don't want to leak the IRQs that we've claimed.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/53031a607fc8412a60024bfb3bb8cd7141f998f5.1616774562.git.robin.murphy@arm.com


Signed-off-by: Will Deacon <will@kernel.org>