[media] mn88472: fix chip id check on probe

A register used to identify chip during probe was overwritten during
firmware download and due to that later probe's for warm chip were
failing. Detect chip from the another register, which is located on
different register bank 2.

Fixes: 94d0eaa4 ("[media] mn88472: move out of staging to media")

Cc: <stable@vger.kernel.org> # v4.8+
Signed-off-by: NAntti Palosaari <crope@iki.fi>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/dvb-frontends/mn88472.c

@@ -488,18 +488,6 @@ static int mn88472_probe(struct i2c_client *client,
 		goto err_kfree;
 	}
 
-	/* Check demod answers with correct chip id */
-	ret = regmap_read(dev->regmap[0], 0xff, &utmp);
-	if (ret)
-		goto err_regmap_0_regmap_exit;
-
-	dev_dbg(&client->dev, "chip id=%02x\n", utmp);
-
-	if (utmp != 0x02) {
-		ret = -ENODEV;
-		goto err_regmap_0_regmap_exit;
-	}
-
 	/*
 	 * Chip has three I2C addresses for different register banks. Used
 	 * addresses are 0x18, 0x1a and 0x1c. We register two dummy clients,
@@ -536,6 +524,18 @@ static int mn88472_probe(struct i2c_client *client,
 	}
 	i2c_set_clientdata(dev->client[2], dev);
 
+	/* Check demod answers with correct chip id */
+	ret = regmap_read(dev->regmap[2], 0xff, &utmp);
+	if (ret)
+		goto err_regmap_2_regmap_exit;
+
+	dev_dbg(&client->dev, "chip id=%02x\n", utmp);
+
+	if (utmp != 0x02) {
+		ret = -ENODEV;
+		goto err_regmap_2_regmap_exit;
+	}
+
 	/* Sleep because chip is active by default */
 	ret = regmap_write(dev->regmap[2], 0x05, 0x3e);
 	if (ret)