perf: arm_pmu: Convert to the new interrupt affinity retrieval API

perf: arm_pmu: Convert to the new interrupt affinity retrieval API

Now that the relevant interrupt controllers are equipped with a callback
returning the affinity of per-CPU interrupts, switch the OF side of the ARM
PMU driver over to this new method.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Will Deacon <will@kernel.org>
Reviewed-by: Jinjie Ruan <ruanjinjie@huawei.com>
Link: https://patch.msgid.link/20251020122944.3074811-9-maz@kernel.org