When turning primitives into line strips this function needs to move
attributes around, but this is not needed in other cases.
Fixes: 1a5bdca2dd ("zink: implement flat shading using inlined uniforms")
Reviewed-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22162>