The IPU has a lot of interrupts. Instead of allocating descs for all
of them, register a linear irq domain and create mappings as needed.
This was listed in the TODO as a prerequisite to move the IPU driver
out of staging.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>