mesa: Do not invalidate shine tables in compute light positions.

mesa: Do not invalidate shine tables in compute light positions.

Since the shine tables are now only used in the tnl lighting stage, where
they are validated through the tnl driver function NotifyMaterialChange
called in tnl/t_vb_light.c, we can not omit calling
_mesa_validate_all_lighting_tables (which only validates the shine tables)
in main/light.c.

Reviewed-by: Alex Deucher <alexdeucher@gmail.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
Signed-off-by: Mathias Froehlich <Mathias.Froehlich@web.de>