dt-bindings: net: fec: add power-domains property

Add optional power domains property

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230328061518.1985981-1-peng.fan@oss.nxp.com


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