dt-bindings: net: add compatible strings for lan969x targets

Add compatible strings for the twelve different lan969x targets that we
support. Either a sparx5-switch or lan9691-switch compatible string
provided on their own, or any lan969x-switch compatible string with a
fallback to lan9691-switch.

Also, add myself as a maintainer.

Reviewed-by: Steen Hegelund <Steen.Hegelund@microchip.com>
Signed-off-by: Daniel Machon <daniel.machon@microchip.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20241024-sparx5-lan969x-switch-driver-2-v2-13-a0b5fae88a0f@microchip.com


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