Parallel to a5efc1d5. Unlike with the Vulkan
backend, we cannot map chunks from the client thread, but we can access the
mapped pointer and increase the map count of already mapped chunks.
Signed-off-by: Zebediah Figura <zfigura@codeweavers.com>
Signed-off-by: Henri Verbeet <hverbeet@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>