ARM: dts: am335x/am437x/dra7: use new "ti, cpsw-mdio" compat string

Add "ti,cpsw-mdio" for am335x/am437x/dra7 SoCs where MDIO is
implemented as part of TI CPSW and, this way, enable PM runtime auto
suspend for Davinci MDIO driver on these paltforms.
Signed-off-by: NGrygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

arch/arm/boot/dts/am33xx.dtsi

@@ -788,7 +788,7 @@
 			status = "disabled";
 
 			davinci_mdio: mdio@4a101000 {
-				compatible = "ti,davinci_mdio";
+				compatible = "ti,cpsw-mdio","ti,davinci_mdio";
 				#address-cells = <1>;
 				#size-cells = <0>;
 				ti,hwmods = "davinci_mdio";

arch/arm/boot/dts/am4372.dtsi

@@ -635,7 +635,7 @@
 			syscon = <&scm_conf>;
 
 			davinci_mdio: mdio@4a101000 {
-				compatible = "ti,am4372-mdio","ti,davinci_mdio";
+				compatible = "ti,am4372-mdio","ti,cpsw-mdio","ti,davinci_mdio";
 				reg = <0x4a101000 0x100>;
 				#address-cells = <1>;
 				#size-cells = <0>;

arch/arm/boot/dts/dra7.dtsi

@@ -1660,7 +1660,7 @@
 			status = "disabled";
 
 			davinci_mdio: mdio@48485000 {
-				compatible = "ti,davinci_mdio";
+				compatible = "ti,cpsw-mdio","ti,davinci_mdio";
 				#address-cells = <1>;
 				#size-cells = <0>;
 				ti,hwmods = "davinci_mdio";