dt-bindings: net: phy: The interrupt property is not mandatory

Unlike what was initially claimed in the PHY binding, the interrupt
property of a PHY can be omitted, and the OS will turn to polling instead.

Document that.
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Rob Herring <robh@kernel.org>

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

@@ -155,7 +155,6 @@ properties:
 
 required:
   - reg
-  - interrupts
 
 examples:
   - |