EKF: remove unused parameter

EKF/common.h

@@ -170,7 +170,6 @@ struct parameters {
 	// process noise
 	float gyro_bias_p_noise;	// process noise for IMU delta angle bias prediction (rad/sec)
 	float accel_bias_p_noise;	// process noise for IMU delta velocity bias prediction (m/sec/sec)
-	float gyro_scale_p_noise;	// process noise for gyro scale factor prediction (N/A)
 	float mage_p_noise;		// process noise for earth magnetic field prediction (Guass/sec)
 	float magb_p_noise;		// process noise for body magnetic field prediction (Guass/sec)
 	float wind_vel_p_noise;		// process noise for wind velocity prediction (m/sec/sec)
@@ -251,7 +250,6 @@ struct parameters {
 		// process noise
 		gyro_bias_p_noise = 2.5e-6f;
 		accel_bias_p_noise = 3.0e-5f;
-		gyro_scale_p_noise = 3.0e-4f;
 		mage_p_noise = 2.5e-3f;
 		magb_p_noise = 5.0e-4f;
 		wind_vel_p_noise = 1.0e-1f;