radeonsi: Define gfx10_format in the common header.

radeonsi: Define gfx10_format in the common header.

So we don't have to have multiple definitions of the struct when
sharing with radv.

While at it put the table properly in a C file so we don't have to
deal with multiple definitions, and the struct definition isn't
in generated source.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5291>