Revert "Revert "Split get_terrain_vert_pos() into valid and get_vpos""

EKF/terrain_estimator.cpp

@@ -150,12 +150,9 @@ void Ekf::fuseHagl()
 	}
 }
 
-// return true if the estimate is fresh
-// return the estimated vertical position of the terrain relative to the NED origin
-bool Ekf::get_terrain_vert_pos(float *ret)
+// return true if the terrain estimate is valid
+bool Ekf::get_terrain_valid()
 {
-	memcpy(ret, &_terrain_vpos, sizeof(float));
-
 	if (_terrain_initialised && _range_data_continuous && !_innov_check_fail_status.flags.reject_hagl) {
 		return true;
 
@@ -164,6 +161,12 @@ bool Ekf::get_terrain_vert_pos(float *ret)
 	}
 }
 
+// get the estimated vertical position of the terrain relative to the NED origin
+void Ekf::get_terrain_vert_pos(float *ret)
+{
+	memcpy(ret, &_terrain_vpos, sizeof(float));
+}
+
 void Ekf::get_hagl_innov(float *hagl_innov)
 {
 	memcpy(hagl_innov, &_hagl_innov, sizeof(_hagl_innov));