mfd: qnap-mcu: Include linux/types.h in qnap-mcu.h shared header

mfd: qnap-mcu: Include linux/types.h in qnap-mcu.h shared header

Relying on other components to include those basic types is unreliable
and may cause compile errors like:

../include/linux/mfd/qnap-mcu.h:13:9: error: unknown type name ‘u32’
   13 |         u32 baud_rate;
      |         ^~~
../include/linux/mfd/qnap-mcu.h:17:9: error: unknown type name ‘bool’
   17 |         bool usb_led;
      |         ^~~~

So make sure, the types used in the header are available.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20250804130726.3180806-2-heiko@sntech.de
Signed-off-by: Lee Jones <lee@kernel.org>