dmaengine: ipu: remove bogus NO_IRQ reference

A workaround for a warning introduced a use of the NO_IRQ
macro that should have been gone for a long time.

It is clear from the code that the value cannot actually
be used, but apparently there was a configuration at
some point that caused a warning, so instead of just
reverting that patch, this rearranges the code in a way that
the warning cannot reappear.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 6ef41cf6 ("dmaengine :ipu: change ipu_irq_handler() to remove compile warning")
Signed-off-by: Vinod Koul <vinod.koul@intel.com>