V4L/DVB: media/az6027: handle -EIO failure

If the az6027_usb_in_op() returns a negative errno ret is -EIO and in
that case the value of b[0] may be undefined.  The original code
assigned 0 to ret, but since it's already 0 now we can skip that.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb/dvb-usb/az6027.c

@@ -701,10 +701,7 @@ static int az6027_ci_poll_slot_status(struct dvb_ca_en50221 *ca, int slot, int o
 	} else
 		ret = 0;
 
-	if (b[0] == 0) {
-		ret = 0;
-
-	} else if (b[0] == 1) {
+	if (!ret && b[0] == 1) {
 		ret = DVB_CA_EN50221_POLL_CAM_PRESENT |
 		      DVB_CA_EN50221_POLL_CAM_READY;
 	}