watchdog: iTCO_wdt: use module_platform_device() macro

Reducing init boilerplate by using the module_platform_device macro.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20201117152214.32244-1-info@metux.net


Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>