ekf2: new gyro bias limit parameter EKF2_GYR_B_LIM

- default is now a more conservative 0.15 rad/s (~8.6 deg/s) instead of the previous hardcoded 20 deg/s

src/modules/ekf2/ekf2_params.c

@@ -1414,6 +1414,19 @@ PARAM_DEFINE_FLOAT(EKF2_ABL_GYRLIM, 3.0f);
  */
 PARAM_DEFINE_FLOAT(EKF2_ABL_TAU, 0.5f);
 
+/**
+ * Gyro bias learning limit.
+ *
+ * The ekf delta angle bias states will be limited to within a range equivalent to +- of this value.
+ *
+ * @group EKF2
+ * @min 0.0
+ * @max 0.4
+ * @unit rad/s
+ * @decimal 3
+ */
+PARAM_DEFINE_FLOAT(EKF2_GYR_B_LIM, 0.15f);
+
 /**
  * Required GPS health time on startup
  *