This can remove special handling of tessfactors which also benifit the nir lower pass which does not handle these as system value. Reviewed-by: Marek Olšák <marek.olsak@amd.com> Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com> Reviewed-by: Timur Kristóf <timur.kristof@gmail.com> Signed-off-by: Qiang Yu <yuq825@gmail.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16705>