hwmon: (wm831x-hwmon) fix checkpatch issues

fixed:
WARNING: static const char * array should probably be static const char * const
+static const char *input_names[] = {

not fixed (will probably provide separate fix later)
ERROR: Macros with multiple statements should be enclosed in a do - while loop
+#define WM831X_NAMED_VOLTAGE(id, name) \
+	WM831X_VOLTAGE(id, name); \
+	static SENSOR_DEVICE_ATTR(in##id##_label, S_IRUGO, show_label,	\
+				  NULL, name)

Signed-off-by: Frans Meulenbroeks <fransmeulenbroeks@gmail.com>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>