hwmon: (pmbus) Add 'phase' parameter where needed for multi-phase support

In preparation for multi-phase support, add 'phase' parameter to read_word
and set_page functions. Actual multi-phase support will be added in
a subsequent patch.

Cc: Vadim Pasternak <vadimp@mellanox.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
diff --git a/drivers/hwmon/pmbus/isl68137.c b/drivers/hwmon/pmbus/isl68137.c
index 515596c..a95835a 100644
--- a/drivers/hwmon/pmbus/isl68137.c
+++ b/drivers/hwmon/pmbus/isl68137.c
@@ -49,7 +49,8 @@ static ssize_t isl68137_avs_enable_store_page(struct i2c_client *client,
 	 * enabling AVS control is the workaround.
 	 */
 	if (op_val == ISL68137_VOUT_AVS) {
-		rc = pmbus_read_word_data(client, page, PMBUS_VOUT_COMMAND);
+		rc = pmbus_read_word_data(client, page, 0xff,
+					  PMBUS_VOUT_COMMAND);
 		if (rc < 0)
 			return rc;