[media] cx231xx-i2c: reduce stack size in bus scan

The cx231xx_do_i2c_scan function needs a lot of stack because
it puts an i2c_client structure on it:

drivers/media/usb/cx231xx/cx231xx-i2c.c: In function 'cx231xx_do_i2c_scan':
drivers/media/usb/cx231xx/cx231xx-i2c.c:518:1: error: the frame size of 1248 bytes is larger than 1152 bytes [-Werror=frame-larger-than=]

This changes it to call i2c_transfer() directly instead, avoiding the
need for the structure.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/usb/cx231xx/cx231xx-i2c.c

@@ -491,20 +491,24 @@ void cx231xx_do_i2c_scan(struct cx231xx *dev, int i2c_port)
 {
 	unsigned char buf;
 	int i, rc;
-	struct i2c_client client;
+	struct i2c_adapter *adap;
+	struct i2c_msg msg = {
+		.flags = I2C_M_RD,
+		.len = 1,
+		.buf = &buf,
+	};
 
 	if (!i2c_scan)
 		return;
 
 	/* Don't generate I2C errors during scan */
 	dev->i2c_scan_running = true;
-
-	memset(&client, 0, sizeof(client));
-	client.adapter = cx231xx_get_i2c_adap(dev, i2c_port);
+	adap = cx231xx_get_i2c_adap(dev, i2c_port);
 
 	for (i = 0; i < 128; i++) {
-		client.addr = i;
-		rc = i2c_master_recv(&client, &buf, 0);
+		msg.addr = i;
+		rc = i2c_transfer(adap, &msg, 1);
+
 		if (rc < 0)
 			continue;
 		dev_info(dev->dev,