watchdog: pnx833x_wdt: Mark as broken

pnx833x_wdt does not compile if enabled. Bit operations expect an unsigned
long as argument. If that is fixed, the build still fails because put_user,
get_user, and copy_to_user are undefined.

Mark it as broken.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>