[PATCH] ppc64 kprobes: correct kprobe registration return values

Add stricter checks during kprobe registration.  Return correct error value so
insmod doesn't succeed.  Also printk reason for registration failure.

Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>