watchdog: twl4030_wdt: add missing mod_devicetable.h include

The driver is using of_device_id and therefore needs to include
mod_devicetable.h header. We used to get this definition indirectly via
inclusion of matrix_keypad.h from twl.h, but we are cleaning up
matrix_keypad.h from unnecessary includes.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220927154611.3330871-1-dmitry.torokhov@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>