platform/x86: intel_scu_wdt: Drop SCU notification

Since SCU code along with the Intel MID watchdog driver has been refactored
in a way that latter will be probed only after the former has been come
to live, the notification code is bogus and not needed. Remove it for good.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>