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>

fs/ubifs/tnc.c

@@ -3275,8 +3275,6 @@ out_unlock:
 	return err;
 }
 
-#ifdef CONFIG_UBIFS_FS_DEBUG
-
 /**
  * dbg_check_inode_size - check if inode size is correct.
  * @c: UBIFS file-system description object
@@ -3343,5 +3341,3 @@ out_unlock:
 	mutex_unlock(&c->tnc_mutex);
 	return err;
 }
-
-#endif /* CONFIG_UBIFS_FS_DEBUG */