irqchip/qcom-pdc: Add irqchip set/get state calls

Add irqchip calls to set/get interrupt state from the parent interrupt
controller. When GPIOs are renabled as interrupt lines, it is desirable
to clear the interrupt state at the GIC. This avoids any unwanted
interrupt as a result of stale pending state recorded when the line was
used as a GPIO.

Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
[Lina: updated commit text, rearranged code]
Signed-off-by: Lina Iyer <ilina@codeaurora.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/1573855915-9841-8-git-send-email-ilina@codeaurora.org