wined3d: Always set GL_PIXEL_UNPACK_BUFFER binding in wined3d_texture_gl_allocate_mutable_storage().
Signed-off-by: Zebediah Figura <zfigura@codeweavers.com>
Signed-off-by: Henri Verbeet <hverbeet@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>