hwmon: Add missing HWMON_T_ALARM

Unfortunately the HWMON_T_ALARM define was missing,
although the associated entry was present in hwmon_temp_attributes.
This is needed to convert drivers to the new interface which use channel
based alarms.

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>