s390/kprobes: Fix %p uses in error messages

Remove %p because the kprobe will be dumped in dump_kprobe().

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>