fix: correct nullptr to FALSE in Bool isPatchShadowed function

Author: bobtista

GeneralsMD/Code/GameEngineDevice/Source/W3DDevice/GameClient/Shadow/W3DVolumetricShadow.cpp

@@ -471,7 +471,7 @@ Bool isPatchShadowed(W3DShadowGeometryHeightmapMesh	*hm_mesh)
 		map=TheTerrainRenderObject->getMap();
 
 	if (!map)
-		return nullptr;
+		return FALSE;
 
 	hm_mesh->buildPolygonNormal( 0, &normal );