[ARM] 3682/2: ARM: Convert ixp4xx to generic irq handling

Patch from Thomas Gleixner

From: Thomas Gleixner <tglx@linutronix.de>

Fixup the conversion to generic irq subsystem.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>