Add array size to servo_endstop_angles (PR#2553)

Marlin/Marlin_main.cpp

 
 #ifdef SERVO_ENDSTOPS
   const int servo_endstops[] = SERVO_ENDSTOPS;
-  const int servo_endstop_angles[][] = SERVO_ENDSTOP_ANGLES;
+  const int servo_endstop_angles[][2] = SERVO_ENDSTOP_ANGLES;
 #endif
 
 #ifdef BARICUDA