i965: Fill in brw_format_for_mesa_format for some non-rendering formats.

i965: Fill in brw_format_for_mesa_format for some non-rendering formats.

This should have no change on driver operation, but it means that when you
wonder why some format isn't supported natively, you can just look at the
table above, instead of wondering if maybe there's an appropriate entry in
the surface formats table that is already supported.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>