watchdog: iTCO_wdt: add platform driver module alias

The recent conversion of iTCO_wdt resulted in the driver no longer
getting loaded automatically, since it no longer has a
MODULE_DEVICE_TABLE() included. As the lpc_ich driver now creates a
platform device, auto-loading can easily be done by having a respective
module alias in place.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Aaron Sierra <asierra@xes-inc.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>