net/usb: initiate sync sequence in sierra_net.c driver

The following patch adds the initiation of the sync sequence to
"sierra_net_bind()". If this step is omitted, the modem will never sync up
with the host and it will not be possible to establish a data connection.
Signed-off-by: NElina Pasheva <epasheva@sierrawireless.com>
Signed-off-by: NRory Filer <rfiler@sierrawireless.com>
Tested-by: NElina Pasheva <epasheva@sierrawireless.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/usb/sierra_net.c

@@ -789,6 +789,9 @@ static int sierra_net_bind(struct usbnet *dev, struct usb_interface *intf)
 	/* prepare sync message from template */
 	memcpy(priv->sync_msg, sync_tmplate, sizeof(priv->sync_msg));
 
+	/* initiate the sync sequence */
+	sierra_net_dosync(dev);
+
 	return 0;
 }