AP_AHRS: Add accessor function for EKF yaw reset request

AP_AHRS: Send yaw reset request to EKF2

libraries/AP_AHRS/AP_AHRS.h

@@ -187,6 +187,9 @@ public:
     // check whether external navigation is providing yaw.  Allows compass pre-arm checks to be bypassed
     virtual bool is_ext_nav_used_for_yaw(void) const { return false; }
     
+    // request EKF yaw reset to try and avoid the need for an EKF lane switch or failsafe
+    virtual void request_yaw_reset(void) {}
+
     // Euler angles (radians)
     float roll;
     float pitch;

libraries/AP_AHRS/AP_AHRS_NavEKF.cpp

@@ -2196,6 +2196,32 @@ void AP_AHRS_NavEKF::check_lane_switch(void)
     }
 }
 
+// request EKF yaw reset to try and avoid the need for an EKF lane switch or failsafe
+void AP_AHRS_NavEKF::request_yaw_reset(void)
+{
+    switch (active_EKF_type()) {
+    case EKFType::NONE:
+        break;
+
+#if CONFIG_HAL_BOARD == HAL_BOARD_SITL
+    case EKFType::SITL:
+        break;
+#endif
+
+#if HAL_NAVEKF2_AVAILABLE
+    case EKFType::TWO:
+        EKF2.requestYawReset();
+        break;
+#endif
+
+#if HAL_NAVEKF3_AVAILABLE
+    case EKFType::THREE:
+        EKF3.requestYawReset();
+        break;
+#endif
+    }
+}
+
 void AP_AHRS_NavEKF::Log_Write()
 {
 #if HAL_NAVEKF2_AVAILABLE

libraries/AP_AHRS/AP_AHRS_NavEKF.h

@@ -287,6 +287,9 @@ public:
     // see if EKF lane switching is possible to avoid EKF failsafe
     void check_lane_switch(void) override;
 
+    // request EKF yaw reset to try and avoid the need for an EKF lane switch or failsafe
+    void request_yaw_reset(void) override;
+
     void Log_Write();
 
     // check whether external navigation is providing yaw.  Allows compass pre-arm checks to be bypassed