AP_SpdHgt_Control: Remove hgt_afe from update_50hz()

libraries/AP_SpdHgtControl/AP_SpdHgtControl.h

@@ -20,7 +20,7 @@ public:
 	// Update the internal state of the height and height rate estimator
 	// Update of the inertial speed rate estimate internal state
 	// Should be called at 50Hz or faster
-	virtual void update_50hz(float height_above_field) = 0;
+	virtual void update_50hz(void) = 0;
 
 	/**
 	   stages of flight so the altitude controller can choose to