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/debug.c b/fs/ubifs/debug.c
index 1934084..139025a 100644
--- a/fs/ubifs/debug.c
+++ b/fs/ubifs/debug.c
@@ -1160,7 +1160,7 @@
 			  "is clean", ui->ui_size, ui->synced_i_size);
 		ubifs_err("i_ino %lu, i_mode %#x, i_size %lld", inode->i_ino,
 			  inode->i_mode, i_size_read(inode));
-		dbg_dump_stack();
+		dump_stack();
 		err = -EINVAL;
 	}
 	spin_unlock(&ui->ui_lock);