seccomp: Add missing compat_ioctl for notify

Executing the seccomp_bpf testsuite under a 64-bit kernel with 32-bit
userland (both s390 and x86) doesn't work because there's no compat_ioctl
handler defined. Add the handler.

Signed-off-by: Sven Schnelle <[email protected]>
Fixes: 6a21cc5 ("seccomp: add a return code to trap to userspace")
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Kees Cook <[email protected]>

Author: svens-s390

kernel/seccomp.c

@@ -1225,6 +1225,7 @@ static const struct file_operations seccomp_notify_ops = {
 	.poll = seccomp_notify_poll,
 	.release = seccomp_notify_release,
 	.unlocked_ioctl = seccomp_notify_ioctl,
+	.compat_ioctl = seccomp_notify_ioctl,
 };
 
 static struct file *init_listener(struct seccomp_filter *filter)