Certain SFP modules (most notably Nokia GPON ones) first check
connectivity on 1000base-x, and switch to 2500base-x afterwards. This
is considered a quirk so the phylink switches the interface to
2500base-x as well.

However, after power-cycling the uDPU device, network interface/SFP module
will not work correctly until the module is re-seated. This patch
resolves this issue by forcing the interface to be brought up in
2500base-x mode by default.

Signed-off-by: Jakov Petrina <jakov.petrina@sartura.hr>
Signed-off-by: Vladimir Vid <vladimir.vid@sartura.hr>
Cc: Luka Perkov <luka.perkov@sartura.hr>

--- a/arch/arm64/boot/dts/marvell/armada-3720-uDPU.dts
+++ b/arch/arm64/boot/dts/marvell/armada-3720-uDPU.dts
@@ -162,7 +162,7 @@
 };
 
 &eth0 {
-	phy-mode = "sgmii";
+	phy-mode = "2500base-x";
 	status = "okay";
 	managed = "in-band-status";
 	phys = <&comphy1 0>;
@@ -170,7 +170,7 @@
 };
 
 &eth1 {
-	phy-mode = "sgmii";
+	phy-mode = "2500base-x";
 	status = "okay";
 	managed = "in-band-status";
 	phys = <&comphy0 1>;