Fix Firmata compatibility

Author: alfran

library.properties

@@ -2,8 +2,8 @@ name=Servo
 version=1.1.2
 author=Michael Margolis, Arduino
 maintainer=Arduino <[email protected]>
-sentence=Allows Arduino/Genuino boards to control a variety of servo motors. 
+sentence=Allows Arduino/Genuino 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.<br />
 category=Device Control
 url=http://www.arduino.cc/en/Reference/Servo
-architectures=avr,sam,samd
+architectures=avr,sam,samd,stm32f4

src/STM32F4/ServoTimers.h

@@ -65,6 +65,10 @@
 // Pin number of unattached pins
 #define NOT_ATTACHED                    (-1)
 
+#define _Nbr_16timers 14 // mumber of STM32F469 Timers
+#define SERVOS_PER_TIMER 4 // Number of timer channels
+
+
 // Default min/max pulse widths (in microseconds) and angles (in
 // degrees).  Values chosen for Arduino compatibility.  These values
 // are part of the public API; DO NOT CHANGE THEM.