V4L/DVB: cx23885: Check register errors

Fix kernel Oops when number of NetUP Dual DVB-S2-CI cards more than
DVB_MAX_ADAPTERS limit.

[mchehab@redhat.com: move the return to the proper place]
Signed-off-by: Abylay Ospan <aospan@netup.ru>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/cx23885/cx23885-dvb.c

@@ -991,6 +991,8 @@ static int dvb_register(struct cx23885_tsport *port)
 	ret = videobuf_dvb_register_bus(&port->frontends, THIS_MODULE, port,
 					&dev->pci->dev, adapter_nr, 0,
 					cx23885_dvb_fe_ioctl_override);
+	if (!ret)
+		return ret;
 
 	/* init CI & MAC */
 	switch (dev->board) {