ARM: 7998/1: IXP4xx: remove deprecated IRQF_DISABLED

This patch removes the use of the IRQF_DISABLED flag
from code in arch/arm/mach-ixp4xx

It's a NOOP since 2.6.35 and it will be removed one day.

Signed-off-by: Michael Opdenacker <michael.opdenacker@free-electrons.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>