arm64: dts: a7k: use phy handle

arm64: dts: a7k: use phy handle

Documentation/devicetree/bindings/net/ethernet-controller.yaml

  phy:
    : #/properties/phy-handle
    deprecated: true

New dts files should not be using deprecated properties.

What should be used is:

  phy-handle:
    : /schemas/types.yaml#/definitions/phandle
    description:
      Specifies a reference to a node representing a PHY device.

Suggested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Elad Nachman <enachman@marvell.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>