hwmon: (core) Rename groups parameter in API to extra_groups

The 'groups' parameter of hwmon_device_register_with_info() and
devm_hwmon_device_register_with_info() is only necessary if extra
non-standard attributes need to be provided. Rename the parameter
to extra_groups and clarify the documentation.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
diff --git a/include/linux/hwmon.h b/include/linux/hwmon.h
index 2588e6e..78d59db 100644
--- a/include/linux/hwmon.h
+++ b/include/linux/hwmon.h
@@ -377,12 +377,12 @@ struct device *
 hwmon_device_register_with_info(struct device *dev,
 				const char *name, void *drvdata,
 				const struct hwmon_chip_info *info,
-				const struct attribute_group **groups);
+				const struct attribute_group **extra_groups);
 struct device *
 devm_hwmon_device_register_with_info(struct device *dev,
-				     const char *name, void *drvdata,
-				     const struct hwmon_chip_info *info,
-				     const struct attribute_group **groups);
+				const char *name, void *drvdata,
+				const struct hwmon_chip_info *info,
+				const struct attribute_group **extra_groups);
 
 void hwmon_device_unregister(struct device *dev);
 void devm_hwmon_device_unregister(struct device *dev);