2.6.7-rc3-mm1 changed cpumask_t from ulong to a struct, causing
compile-time errors in arch/ppc/kernel/irq.c.

Proposed fix below. Tested on a G3.
Signed-off-by: Mikael Pettersson <mikpe@csd.uu.se>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>