drm/msm/sde: skip IRQ_NOAUTOEN if pwr_en event called before irq install

When irq is preinstalled, IRQ_NOAUTOEN will block irq for power event,
and if there was already a power enable event before, the next power
disable event after irq install will cause irq depth equals to 2 and
the next power enable event will not be able to enable the actual irq.

The change will check previous power event status, and skip IRQ_NOAUTOEN
if power is already enabled before irq install.

Change-Id: I20a0e65ef729e006c669e737e61fe1432090328e
Signed-off-by: Xiaowen Wu <wxiaowen@codeaurora.org>