dt-bindings: net: sff,sfp: Fix "interrupts" property typo

The example has "interrupt" property which is not a defined property. It
should be "interrupts" instead. "interrupts" also should not contain a
phandle.

Signed-off-by: Rob Herring (Arm) <[e-mail]>
Reviewed-by: Andrew Lunn <[e-mail]>
Acked-by: Conor Dooley <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

Documentation/devicetree/bindings/net/sff,sfp.yaml

···
         pinctrl-names = "default";
         pinctrl-0 = <&cpm_phy0_pins &cps_phy0_pins>;
         reg = <0>;
-        interrupt = <&cpm_gpio2 18 IRQ_TYPE_EDGE_FALLING>;
+        interrupts = <18 IRQ_TYPE_EDGE_FALLING>;
         sfp = <&sfp2>;
       };
     };