MAINTAINERS: Re-add cancelled Renesas driver sections

Removing full driver sections also removed mailing list entries, causing
submitters of future patches to forget CCing these mailing lists.

Hence re-add the sections for the Renesas Ethernet AVB, R-Car SATA, and
SuperH Ethernet drivers.  Add people who volunteered to maintain these
drivers (thanks a lot!), and mark all of them as supported.

Fixes: 6e90b675 ("MAINTAINERS: Remove some entries due to various compliance requirements.")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Acked-by: Niklas Cassel <cassel@kernel.org>
Acked-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Paul Barker <paul.barker.ct@bp.renesas.com>
Link: https://patch.msgid.link/4b2105332edca277f07ffa195796975e9ddce994.1731319098.git.geert+renesas@glider.be


Signed-off-by: Jakub Kicinski <kuba@kernel.org>