[media] a8293: add small sleep in order to settle LNB voltage

PCTV 461e requires that small delay.
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/dvb-frontends/a8293.c

@@ -96,6 +96,8 @@ static int a8293_set_voltage(struct dvb_frontend *fe,
 	if (ret)
 		goto err;
 
+	usleep_range(1500, 50000);
+
 	return ret;
 err:
 	dev_dbg(&priv->i2c->dev, "%s: failed=%d\n", __func__, ret);