fmu: remove unused include and variable

src/drivers/px4fmu/CMakeLists.txt

@@ -38,7 +38,6 @@ px4_add_module(
 		fmu.cpp
 	DEPENDS
 		arch_io_pins
-		circuit_breaker
 		mixer
 		mixer_module
 		output_limit

src/drivers/px4fmu/fmu.cpp

@@ -48,7 +48,6 @@
 #include <drivers/drv_mixer.h>
 #include <drivers/drv_pwm_output.h>
 #include <lib/cdev/CDev.hpp>
-#include <lib/circuit_breaker/circuit_breaker.h>
 #include <lib/mathlib/mathlib.h>
 #include <lib/mixer_module/mixer_module.hpp>
 #include <lib/parameters/param.h>
@@ -166,8 +165,6 @@ public:
 private:
 	MixingOutput _mixing_output{*this, MixingOutput::SchedulingPolicy::Auto, true};
 
-	static constexpr uint8_t MAX_ACTUATORS = DIRECT_PWM_OUTPUT_CHANNELS;
-
 	Mode		_mode{MODE_NONE};
 
 	unsigned	_pwm_default_rate{50};