[PATCH] ppc64: silence perfmon exception warnings

We dont need to use the PERFMON exception on POWER5, in fact the firmware
returns an error.  Due to this just remove the warning.

Also now that we have proper runlatch support we can remove the bootup
hack.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>