Add description and set category for eTSEC device so it shows up
better in -device help.
Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Reviewed-by: Bernhard Beschow <shentey@gmail.com>
Message-ID: <20250218155407.838774E600E@zero.eik.bme.hu>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>