ARM: dts: am57xx-beagle-x15: implement errata "Ethernet RGMII2 Limited to 10/100 Mbps"

According to errata i880 description the speed of Ethernet port 1 on AM572x
SoCs rev 1.1 should be limited to 10/100Mbps, because RGMII2 Switching
Characteristics are not compatible with 1000 Mbps operation [1].
The issue is fixed with Rev 2.0 silicon.

Hence, rework Beagle-X15 and Begale-X15-revb1 to use phy-handle instead of
phy_id and apply corresponding limitation to the Ethernet Phy 1.

[1] http://www.ti.com/lit/er/sprz429j/sprz429j.pdf

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/am57xx-beagle-x15-common.dtsi

@@ -421,19 +421,29 @@
 			      <&dra7_pmx_core 0x3f8>;
 };
 
+&davinci_mdio {
+	phy0: ethernet-phy@1 {
+		reg = <1>;
+	};
+
+	phy1: ethernet-phy@2 {
+		reg = <2>;
+	};
+};
+
 &mac {
 	status = "okay";
 	dual_emac;
 };
 
 &cpsw_emac0 {
-	phy_id = <&davinci_mdio>, <1>;
+	phy-handle = <&phy0>;
 	phy-mode = "rgmii";
 	dual_emac_res_vlan = <1>;
 };
 
 &cpsw_emac1 {
-	phy_id = <&davinci_mdio>, <2>;
+	phy-handle = <&phy1>;
 	phy-mode = "rgmii";
 	dual_emac_res_vlan = <2>;
 };

arch/arm/boot/dts/am57xx-beagle-x15-revb1.dts

@@ -22,3 +22,8 @@
 	vmmc-supply = <&vdd_3v3>;
 	vmmc-aux-supply = <&ldo1_reg>;
 };
+
+/* errata i880 "Ethernet RGMII2 Limited to 10/100 Mbps" */
+&phy1 {
+	max-speed = <100>;
+};

arch/arm/boot/dts/am57xx-beagle-x15.dts

@@ -22,3 +22,8 @@
 &mmc1 {
 	vmmc-supply = <&ldo1_reg>;
 };
+
+/* errata i880 "Ethernet RGMII2 Limited to 10/100 Mbps" */
+&phy1 {
+	max-speed = <100>;
+};