hwmon: (pmbus) Replace EINVAL return codes with more appropriate errors

EINVAL was over-used in the code. Replace it with more appropriate errors.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Reviewed-by: Robert Coulson <robert.coulson@ericsson.com>
diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c
index 640a9c9..1536db6 100644
--- a/drivers/hwmon/pmbus/ucd9000.c
+++ b/drivers/hwmon/pmbus/ucd9000.c
@@ -75,7 +75,7 @@
 	switch (reg) {
 	case PMBUS_FAN_CONFIG_12:
 		if (page)
-			return -EINVAL;
+			return -ENXIO;
 
 		ret = ucd9000_get_fan_config(client, 0);
 		if (ret < 0)
@@ -89,7 +89,7 @@
 		break;
 	case PMBUS_FAN_CONFIG_34:
 		if (page)
-			return -EINVAL;
+			return -ENXIO;
 
 		ret = ucd9000_get_fan_config(client, 2);
 		if (ret < 0)