mesa: add OES_texture_buffer and EXT_texture_buffer extension to table

mesa: add OES_texture_buffer and EXT_texture_buffer extension to table

We need to add a new bit since the GL ES exts require functionality from
a combination of texture buffer extensions as well as images (for
imageBuffer) support. Additionally, not all GPUs support all the texture
buffer functionality (e.g. rgb32 isn't supported by nv50).

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>