docs/specs: annotate MESA_agp_offset as obsolete

No Mesa driver has implemented the extension in ages. Seemingly non Mesa
drivers don't implement it either.

As mentioned by Ian, the extension is effectively superseded by
ARB_vertex_buffer_object.

v2: Move the extension to OLD/

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Brian Paul <brianp@vmware.com> (v1)
Reviewed-by: Adam Jackson <ajax@redhat.com> (v1)
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
2 files changed