UBIFS: get rid of dbg_dump_stack

In case of errors we almost always need the stack dump - it makes no sense
to compile it out. Remove the 'dbg_dump_stack()' function completely.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
diff --git a/fs/ubifs/orphan.c b/fs/ubifs/orphan.c
index c542c73..be18de8 100644
--- a/fs/ubifs/orphan.c
+++ b/fs/ubifs/orphan.c
@@ -159,7 +159,7 @@
 	}
 	spin_unlock(&c->orphan_lock);
 	dbg_err("missing orphan ino %lu", (unsigned long)inum);
-	dbg_dump_stack();
+	dump_stack();
 }
 
 /**