ARM: dts: imx6ul-prti6g: configure ethernet reference clock parent

On this board the PHY is the ref clock provider. So, configure ethernet
reference clock as input.

Without this patch we have relatively high amount of dropped packets.
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx6ul-prti6g.dts

@@ -26,6 +26,7 @@ clock_ksz8081_out: clock-ksz8081-out {
 		compatible = "fixed-clock";
 		#clock-cells = <0>;
 		clock-frequency = <50000000>;
+		clock-output-names = "enet1_ref_pad";
 	};
 
 	leds {
@@ -60,6 +61,13 @@ &can2 {
 	status = "okay";
 };
 
+&clks {
+	clocks = <&ckil>, <&osc>, <&ipp_di0>, <&ipp_di1>, <&clock_ksz8081_out>;
+	clock-names = "ckil", "osc", "ipp_di0", "ipp_di1", "enet1_ref_pad";
+	assigned-clocks = <&clks IMX6UL_CLK_ENET1_REF_SEL>;
+	assigned-clock-parents = <&clock_ksz8081_out>;
+};
+
 &ecspi1 {
 	cs-gpios = <&gpio4 26 GPIO_ACTIVE_LOW>;
 	pinctrl-names = "default";
@@ -85,12 +93,6 @@ &fec1 {
 	pinctrl-0 = <&pinctrl_eth1>;
 	phy-mode = "rmii";
 	phy-handle = <&rmii_phy>;
-	clocks = <&clks IMX6UL_CLK_ENET>,
-		 <&clks IMX6UL_CLK_ENET_AHB>,
-		 <&clks IMX6UL_CLK_ENET_PTP>,
-		 <&clock_ksz8081_out>;
-	clock-names = "ipg", "ahb", "ptp",
-		      "enet_clk_ref";
 	status = "okay";
 
 	mdio {