gpu: ipu-v3: Reset IPU before activating IRQ

If we don't come out of a clean reset, make sure no IRQ is fired before
everything is setup by resetting the IPU before activating the interrupt
handlers.

Signed-off-by: David Jander <david@protonic.nl>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>