Staging: gdm724x: gdm_usb: added error checking in do_tx()

Added error checking for alloc_tx_struct in do_tx()
Signed-off-by: Abel Moyo <abelmoyo.ab@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/gdm724x/gdm_usb.c

@@ -682,6 +682,10 @@ static void do_tx(struct work_struct *work)
 		}
 
 		t = alloc_tx_struct(TX_BUF_SIZE);
+		if (t == NULL) {
+			spin_unlock_irqrestore(&tx->lock, flags);
+			return;
+		}
 		t->callback = NULL;
 		t->tx = tx;
 		t->is_sdu = 1;