ARM: orion: switch to a per-platform handle_irq() function

ARM: orion: switch to a per-platform handle_irq() function

Moving to the Device Tree implies having CONFIG_MULTI_IRQ_HANDLER
enabled, even for non-DT platforms (if we want both DT and non-DT
platforms to be supported in a single kernel).

However, the common CONFIG_MULTI_IRQ_HANDLER handler for non-DT
platforms in plat-orion/irq.c doesn't match the needs of
Orion5x. Also, it doesn't make much sense for orion_irq_init() to
register the multi-IRQ handler: orion_irq_init() is called once for
each IRQ cause/mask tuple, while the multi-IRQ handler only needs to
be registered once.

To solve this problem, we move the multi-IRQ handle in per-platform
code: mach-kirkwood/irq.c and mach-dove/irq.c. The Orion5x variant
will be introduced in a followup commit. Of course, this code will
ultimately be completely removed once all boards are converted to the
Device Tree.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Link: https://lkml.kernel.org/r/1398202002-28530-23-git-send-email-thomas.petazzoni@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>