kernel/exit.c: quieten greatest stack depth printk

Many targets enable CONFIG_DEBUG_STACK_USAGE, and while the information
is useful, it isn't worthy of pr_warn().  Reduce it to pr_info().

Link: http://lkml.kernel.org/r/1466982072-29836-1-git-send-email-anton@ozlabs.org
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/exit.c

@@ -715,7 +715,7 @@ static void check_stack_usage(void)
 
 	spin_lock(&low_water_lock);
 	if (free < lowest_to_date) {
-		pr_warn("%s (%d) used greatest stack depth: %lu bytes left\n",
+		pr_info("%s (%d) used greatest stack depth: %lu bytes left\n",
 			current->comm, task_pid_nr(current), free);
 		lowest_to_date = free;
 	}