ARM: dts: iwg23s-sbc: Add pinctl support for EtherAVB

Adding pinctrl support for EtherAVB interface.
Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a77470-iwg23s-sbc.dts

@@ -60,6 +60,9 @@ vccq_sdhi2: regulator-vccq-sdhi2 {
 };
 
 &avb {
+	pinctrl-0 = <&avb_pins>;
+	pinctrl-names = "default";
+
 	phy-handle = <&phy3>;
 	phy-mode = "gmii";
 	renesas,no-ether-link;
@@ -82,6 +85,11 @@ &extal_clk {
 };
 
 &pfc {
+	avb_pins: avb {
+		groups = "avb_mdio", "avb_gmii_tx_rx";
+		function = "avb";
+	};
+
 	mmc_pins_uhs: mmc_uhs {
 		groups = "mmc_data8", "mmc_ctrl";
 		function = "mmc";