Fix integer overflow when loading time exceeds uint16 range

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@11900 8aca7d54-2c30-db11-9de9-000461428c89

Author: ceeac

src/simutrans/descriptor/vehicle_desc.h

@@ -238,7 +238,7 @@ class vehicle_desc_t : public obj_desc_transport_related_t {
 	bool can_follow_any() const { return trailer_count==0; }
 
 	uint16 get_capacity() const { return capacity; }
-	uint16 get_loading_time() const { return loading_time; } // ms per full loading/unloading
+	uint32 get_loading_time() const { return loading_time; } // ms per full loading/unloading
 	uint32 get_weight() const { return weight; }
 	uint32 get_power() const { return power; }
 	sint64 get_running_cost() const { return running_cost; }

src/simutrans/simconvoi.cc

@@ -3036,7 +3036,7 @@ void convoi_t::hat_gehalten(halthandle_t halt)
 			continue;
 		}
 
-		const uint32_t ms_for_full_load = v->get_desc()->get_loading_time();
+		const uint32 ms_for_full_load = v->get_desc()->get_loading_time();
 
 		uint32 min_loading_step_time = ms_for_full_load / v->get_cargo_max() + 1;
 		time = max(time, min_loading_step_time);