cxd2820r: fix gpio null pointer dereference

commit 0ffb94b6 upstream.

Setting GPIOs during probe causes null pointer deference when
GPIOLIB was not selected by Kconfig. Initialize driver private
field before calling set gpios.

It is regressing bug since 4.9.

Fixes: 07fdf7d9 ("[media] cxd2820r: add I2C driver bindings")
Reported-by: Chris Rankin <rankincj@gmail.com>
Tested-by: Chris Rankin <rankincj@gmail.com>
Tested-by: Håkan Lennestål <hakan.lennestal@gmail.com>
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/media/dvb-frontends/cxd2820r_core.c

@@ -615,6 +615,7 @@ static int cxd2820r_probe(struct i2c_client *client,
 	}
 
 	priv->client[0] = client;
+	priv->fe.demodulator_priv = priv;
 	priv->i2c = client->adapter;
 	priv->ts_mode = pdata->ts_mode;
 	priv->ts_clk_inv = pdata->ts_clk_inv;
@@ -697,7 +698,6 @@ static int cxd2820r_probe(struct i2c_client *client,
 	memcpy(&priv->fe.ops, &cxd2820r_ops, sizeof(priv->fe.ops));
 	if (!pdata->attach_in_use)
 		priv->fe.ops.release = NULL;
-	priv->fe.demodulator_priv = priv;
 	i2c_set_clientdata(client, priv);
 
 	/* Setup callbacks */