genirq: Move suspend/resume logic into irq/pm code

No functional change. Preparatory patch for cleaning up the suspend
abort functionality. Update the comments while at it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --cc kernel/irq/internals.h
Simple merge

diff --cc kernel/irq/manage.c
Simple merge

diff --cc kernel/irq/pm.c
Simple merge