ARM: dts: mvebu: add "marvell,prestera" to PP nodes

The compatible string "marvell,prestera" allows drivers to have code
common to any prestera variant.
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>

arch/arm/boot/dts/armada-xp-98dx3236.dtsi

@@ -243,7 +243,7 @@ switch: switch@a8000000 {
 			ranges = <0 MBUS_ID(0x03, 0x00) 0 0x100000>;
 
 			pp0: packet-processor@0 {
-				compatible = "marvell,prestera-98dx3236";
+				compatible = "marvell,prestera-98dx3236", "marvell,prestera";
 				reg = <0 0x4000000>;
 				interrupts = <33>, <34>, <35>;
 				dfx = <&dfx>;

arch/arm/boot/dts/armada-xp-98dx3336.dtsi

@@ -35,5 +35,5 @@ resume@20980 {
 };
 
 &pp0 {
-	compatible = "marvell,prestera-98dx3336";
+	compatible = "marvell,prestera-98dx3336", "marvell,prestera";
 };

arch/arm/boot/dts/armada-xp-98dx4251.dtsi

@@ -49,6 +49,6 @@ sdio_pins: sdio-pins {
 };
 
 &pp0 {
-	compatible = "marvell,prestera-98dx4251";
+	compatible = "marvell,prestera-98dx4251", "marvell,prestera";
 	interrupts = <33>, <34>, <35>, <36>;
 };