kernel: disable CONFIG_IRQ_ALL_CPUS by default

this fixes the mpc85xx build error

Signed-off-by: John Crispin <blogic@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@41477 3c298f89-4303-0410-b956-a3cf2f4a3e73