qed: prevent possible double-frees of the chains

Zero-initialize chain on qed_chain_free(), so it couldn't be freed
twice and provoke undefined behaviour.
Signed-off-by: Alexander Lobakin <alobakin@marvell.com>
Signed-off-by: Igor Russkikh <irusskikh@marvell.com>
Signed-off-by: Michal Kalderon <michal.kalderon@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/qlogic/qed/qed_chain.c

@@ -92,8 +92,10 @@ void qed_chain_free(struct qed_dev *cdev, struct qed_chain *chain)
 		qed_chain_free_pbl(cdev, chain);
 		break;
 	default:
-		break;
+		return;
 	}
+
+	qed_chain_init_mem(chain, NULL, 0);
 }
 
 static int