Actually allow full range in FMU driver

src/drivers/px4fmu/fmu.cpp

@@ -908,7 +908,7 @@ PX4FMU::pwm_ioctl(file *filp, int cmd, unsigned long arg)
 		/* FALLTHROUGH */
 	case PWM_SERVO_SET(1):
 	case PWM_SERVO_SET(0):
-		if (arg < 2100) {
+		if (arg <= 2100) {
 			up_pwm_servo_set(cmd - PWM_SERVO_SET(0), arg);
 		} else {
 			ret = -EINVAL;