UBIFS: rename dbg_check_dir_size function

Since this function is not only about size checking, rename it to
'dbg_check_dir()'.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 529be05..de82c5d 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -94,7 +94,7 @@
 			   ubifs_compr_name(ui->compr_type));
 	}
 
-	err = dbg_check_dir_size(c, inode);
+	err = dbg_check_dir(c, inode);
 	return err;
 }