gallium: use gl shader types as the basis for the gallium ones

gallium: use gl shader types as the basis for the gallium ones

This should enable a rename transistion.

Trace needs to swap over to a non-generated version, but that should be fine.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17747>