drivers: GICv3: Check IRQ state in gic_set_affinity()

If both irq chip and external interrupt controller implement
irq_disable callback then disable_irq() API disables an interrupt
at external interrupt controller level but does not disable at GIC
level due to lazy approach. During the cpu hotplug gic_set_affinity()
checks whether IRQ enabled at GIC level or not and enabling IRQ at
external interrupt controller level too after IRQ migration to new cpu
even though IRQ was disabled. So add a check in gic_set_affinity()
to check whether IRQ was disabled in descriptor before enabling.

Change-Id: Iba81881c08102ac0a5960c3a97c1c9f8c477bd56
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>