Patch from SAN People

On some ARM-based processor's (eg, Atmel's AT91RM9200) it is necessary
to signal the end-of-interrupt to the interrupt controller. This is
necessary so it can restore its internal priority levels, etc.
This patch is equivalent to the version in the current 2.4 kernels.
Patch now updated to 2.6.11

Signed-off-by: Andrew Victor
Signed-off-by: Russell King