Patch from Lennert Buytenhek

Compiling one kernel that supports both ixdp2400 and ixdp2800 gives
an error, as a copy of the ixdp2400 irq init routing accidentally
ended up in ixdp2800.c somehow.
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Deepak Saxena
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>