ARM: dts: imx7-mba7: remove un-used "phy-reset-delay" property

Remove un-used "phy-reset-delay" property which found when do dtbs_check
(set additionalProperties: false in fsl,fec.yaml).
Double check current driver and commit history, "phy-reset-delay" never comes
up, so it should be safe to remove it.

$ make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- dtbs_check DT_SCHEMA_FILES=Documentation/devicetree/bindings/net/fsl,fec.yaml
arch/arm/boot/dts/imx7d-mba7.dt.yaml: ethernet@30be0000: 'phy-reset-delay' does not match any of the regexes: 'pinctrl-[0-9]+'
arch/arm/boot/dts/imx7d-mba7.dt.yaml: ethernet@30bf0000: 'phy-reset-delay' does not match any of the regexes: 'pinctrl-[0-9]+'
/arch/arm/boot/dts/imx7s-mba7.dt.yaml: ethernet@30be0000: 'phy-reset-delay' does not match any of the regexes: 'pinctrl-[0-9]+'

Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>