dt-bindings: net: Cleanup MDIO node schemas

The schemas for MDIO bus nodes range from missing to duplicating
everything in mdio.yaml. The MDIO bus node schemas only need to
reference mdio.yaml, define any binding specific properties, and define
'unevaluatedProperties: false'. This ensures that MDIO nodes only
contain defined properties. With this, any duplicated properties can
be removed.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Vivien Didelot <vivien.didelot@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Vladimir Oltean <olteanv@gmail.com>
Cc: Joakim Zhang <qiangqing.zhang@nxp.com>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Cc: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Cc: Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
Cc: "Fernández Rojas" <noltari@gmail.com>
Cc: John Crispin <john@phrozen.org>
Cc: "G. Jaya Kumaran" <vineetha.g.jaya.kumaran@intel.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Jose Abreu <joabreu@synopsys.com>
Cc: netdev@vger.kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20220105151009.3093506-1-robh@kernel.org