Add compatibility with splitted mbed cores

Author: facchinm

library.properties

@@ -6,4 +6,4 @@ sentence=Allows Arduino boards to control a variety of servo motors.
 paragraph=This library can control a great number of servos.<br />It makes careful use of timers: the library can control 12 servos using only 1 timer.<br />On the Arduino Due you can control up to 60 servos.
 category=Device Control
 url=https://www.arduino.cc/reference/en/libraries/servo/
-architectures=avr,megaavr,sam,samd,nrf52,stm32f4,mbed
+architectures=avr,megaavr,sam,samd,nrf52,stm32f4,mbed,mbed_nano,mbed_portenta,mbed_rp2040