irqchip: qcom: mpm: Add irq_set_wake support to mpm irqchip

GIC driver started supporting irq_set_wake call and stores
wakeup capable irq in wakeup_irqs with commit
fc8e11b2.

Since MPM is currently not forwarding irq_set_wake calls
to its parent GIC, device is not able to wake up from
suspend since no wakeup capable IRQ is present in GIC's
wakeup_irqs.

Add support in MPM irq_chip to forward irq_set_wake calls
to its parent GIC to resolve this.

Change-Id: I4b7398ded02c544602b12c5b0ca8f392f7ee1e46
Signed-off-by: Raghavendra Kakarla <rkakarla@codeaurora.org>
Signed-off-by: Haribabu Gattem <haribabu@codeaurora.org>