Replace CONFIG_IRQ_ALL_CPUS with a boot option (noirqdistrib).  Compile
options arent much use on a distro kernel.  This also removes the ppc64 use
of smp_threads_ready.

I considered removing the option completely but we have had problems in the
past with firmware bugs.  In those cases the boot option would have helped.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>