kernel/printk/index.c: fix memory leak with using debugfs_lookup()

When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time.  To make things simpler, just
call debugfs_lookup_and_remove() instead which handles all of the logic
at once.

Cc: Chris Down <chris@chrisdown.name>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20230202151411.2308576-1-gregkh@linuxfoundation.org

kernel/printk/index.c

@@ -145,7 +145,7 @@ static void pi_create_file(struct module *mod)
 #ifdef CONFIG_MODULES
 static void pi_remove_file(struct module *mod)
 {
-	debugfs_remove(debugfs_lookup(pi_get_module_name(mod), dfs_index));
+	debugfs_lookup_and_remove(pi_get_module_name(mod), dfs_index);
 }
 
 static int pi_module_notify(struct notifier_block *nb, unsigned long op,