dt-bindings: net: ipq4019-mdio: add IPQ8074 compatible

Allow using IPQ8074 specific compatible along with the fallback IPQ4019
one in order to be able to specify which compatibles require clocks to
be able to validate them via schema.

Signed-off-by: Robert Marko <robimarko@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20221114194734.3287854-2-robimarko@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>