genirq: Split up irq_pm_check_wakeup()

Let the calling code check for the IRQD_WAKEUP_ARMED flag to prepare for a
live lock mitigation in the edge type handler.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Liangyan <liangyan.peng@bytedance.com>
Link: https://lore.kernel.org/all/20250718185312.012392426@linutronix.de