hwmon: (pmbus) Drop check for PMBus revision register in probe function

Some PMBus devices do not support the PMBus revision register, so don't check
if it exists.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Reviewed-by: Robert Coulson <robert.coulson@ericsson.com>
Cc: stable.kernel.org # 2.6.39

drivers/hwmon/pmbus_core.c

@@ -1430,14 +1430,9 @@ int pmbus_do_probe(struct i2c_client *client, const struct i2c_device_id *id,
 	i2c_set_clientdata(client, data);
 	mutex_init(&data->update_lock);
 
-	/*
-	 * Bail out if status register or PMBus revision register
-	 * does not exist.
-	 */
-	if (i2c_smbus_read_byte_data(client, PMBUS_STATUS_BYTE) < 0
-	    || i2c_smbus_read_byte_data(client, PMBUS_REVISION) < 0) {
-		dev_err(&client->dev,
-			"Status or revision register not found\n");
+	/* Bail out if PMBus status register does not exist. */
+	if (i2c_smbus_read_byte_data(client, PMBUS_STATUS_BYTE) < 0) {
+		dev_err(&client->dev, "PMBus status register not found\n");
 		ret = -ENODEV;
 		goto out_data;
 	}