disp: msm: sde: add pm QoS vote on CPU receiving display IRQ

Add a QoS vote on CPU receiving display interrupt. QoS vote
will prevent that CPU from going into low power mode avoiding
possible interrupt latency. Using irq notifier, display will
receive notification when display IRQ has switched CPUs and
will adjust the vote accordingly. The vote is also removed and
requested whenever display IRQ is enabled or disabled.

Change-Id: I94b4501896b4b20b37deaca90d6b5ff883d56621
Signed-off-by: Samantha Tran <samtran@codeaurora.org>