vaallocator: Do not try derive image for d3d backend
Current codes try derive image in _update_image_info first, if derive returns no error, the va_allocator->info is the one from derived image, but in va_map_unlocked, we disable derive manner for d3d backend because it doesn't seem to work, this will cause issue for d3d path, i.e. possibly using derived info in va_get_image to do mapping... This patch disables derive image for d3d backend in _update_image_info, to ensure we only use info from va_create_image for d3d path.