Bluetooth: hci_uart: check the return value of recv()

Check the return value of hu->proto->recv() in hci_uart_tty_receive()
the recv() may return error, check it, not add this to statistics.

Signed-off-by: Jiejing Zhang <jiejing.zhang@freescale.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
diff --git a/drivers/bluetooth/hci_ath.c b/drivers/bluetooth/hci_ath.c
index bd34406..4093935 100644
--- a/drivers/bluetooth/hci_ath.c
+++ b/drivers/bluetooth/hci_ath.c
@@ -201,8 +201,13 @@
 /* Recv data */
 static int ath_recv(struct hci_uart *hu, void *data, int count)
 {
-	if (hci_recv_stream_fragment(hu->hdev, data, count) < 0)
+	int ret;
+
+	ret = hci_recv_stream_fragment(hu->hdev, data, count);
+	if (ret < 0) {
 		BT_ERR("Frame Reassembly Failed");
+		return ret;
+	}
 
 	return count;
 }