autofs: fix pr_debug() message

This isn't a return value, so change the message to indicate the status is
the result of may_umount().

(or locate pr_debug() after put_user() with the same message)

Link: http://lkml.kernel.org/r/20160812024836.12352.74628.stgit@pluto.themaw.net
Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Signed-off-by: Ian Kent <ikent@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/autofs4/root.c

@@ -840,7 +840,7 @@ static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
 	if (may_umount(mnt))
 		status = 1;
 
-	pr_debug("returning %d\n", status);
+	pr_debug("may umount %d\n", status);
 
 	status = put_user(status, p);