UBIFS: remove Kconfig debugging option

Have the debugging stuff always compiled-in instead. It simplifies maintanance
a lot.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
diff --git a/fs/ubifs/commit.c b/fs/ubifs/commit.c
index 4f795d1..5da20c19 100644
--- a/fs/ubifs/commit.c
+++ b/fs/ubifs/commit.c
@@ -496,7 +496,9 @@
 	return ret;
 }
 
-#ifdef CONFIG_UBIFS_FS_DEBUG
+/*
+ * Everything below is related to debugging.
+ */
 
 /**
  * struct idx_node - hold index nodes during index tree traversal.
@@ -734,5 +736,3 @@
 		err = -EINVAL;
 	return err;
 }
-
-#endif /* CONFIG_UBIFS_FS_DEBUG */