staging: mt7621-dts: fix pinctrl-0 items to be size-1 items on ethernet

Fix pinctrl-0 items under the ethernet node to be size-1 items.
Current notation would be used on specifications with non-zero cells.

Fixes: 0a93c0d7 ("staging: mt7621-dts: fix pinctrl properties for ethernet")
Reported-by: NSander Vanheule <sander@svanheule.net>
Signed-off-by: NArınç ÜNAL <arinc.unal@arinc9.com>
Link: https://lore.kernel.org/r/20220215081725.3463-1-arinc.unal@arinc9.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/mt7621-dts/mt7621.dtsi

@@ -323,7 +323,7 @@
 		mediatek,ethsys = <&sysc>;
 
 		pinctrl-names = "default";
-		pinctrl-0 = <&rgmii1_pins &rgmii2_pins &mdio_pins>;
+		pinctrl-0 = <&mdio_pins>, <&rgmii1_pins>, <&rgmii2_pins>;
 
 		gmac0: mac@0 {
 			compatible = "mediatek,eth-mac";