navigator: don't check reached for land waypoints

src/modules/navigator/mission_block.cpp

@@ -69,6 +69,10 @@ MissionBlock::~MissionBlock()
 bool
 MissionBlock::is_mission_item_reached()
 {
+	/* don't check landed WPs */
+	if (_mission_item.nav_cmd == NAV_CMD_LAND) {
+		return false;
+	}
 	/* TODO: count turns */
 #if 0
 	if ((_mission_item.nav_cmd == NAV_CMD_LOITER_TURN_COUNT ||