misc: vmw_balloon: 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: Nadav Amit <namit@vmware.com>
Cc: VMware PV-Drivers Reviewers <pv-drivers@vmware.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20230202141100.2291188-1-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/vmw_balloon.c

@@ -1709,7 +1709,7 @@ static void __init vmballoon_debugfs_init(struct vmballoon *b)
 static void __exit vmballoon_debugfs_exit(struct vmballoon *b)
 {
 	static_key_disable(&balloon_stat_enabled.key);
-	debugfs_remove(debugfs_lookup("vmmemctl", NULL));
+	debugfs_lookup_and_remove("vmmemctl", NULL);
 	kfree(b->stats);
 	b->stats = NULL;
 }