chore(servo): remove useless define

ARDUINO_ARCH_STM32F4 was for first stm32 core version.
One core per series.

Signed-off-by: Frederic Pillon <frederic.pillon@st.com>

Author: fpistm

libraries/Servo/src/Servo.h

@@ -73,7 +73,6 @@
 
 #define INVALID_SERVO         255     // flag indicating an invalid servo index
 
-#if !defined(ARDUINO_ARCH_STM32F4)
 
 typedef struct  {
   uint8_t nbr;            // a pin number from 0 to 255
@@ -103,4 +102,3 @@ class Servo {
 };
 
 #endif
-#endif