Fixes Wine test failure in d3d11 test_copy_subresource_region().
The test failure could be unstable as there was read after data
end in glTexSubImage2D() called from wined3d_texture_gl_upload_data().
Signed-off-by: Paul Gofman <gofmanp@gmail.com>
Signed-off-by: Henri Verbeet <hverbeet@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>