powerpc/fsl/dts: Fix phy-connection-type for fm1mac3

Property phy-connection-type contains invalid value "sgmii-2500" per scheme
defined in file ethernet-controller.yaml.

Correct phy-connection-type value should be "2500base-x".

Signed-off-by: Pali Rohár <[e-mail]>
Fixes: 84e0f1c13806 ("powerpc/mpc85xx: Add MDIO bus muxing support to the board device tree(s)")
Acked-by: Scott Wood <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

arch/powerpc/boot/dts/fsl/t1023rdb.dts

···
 
 			fm1mac3: ethernet@e4000 {
 				phy-handle = <&sgmii_aqr_phy3>;
-				phy-connection-type = "sgmii-2500";
+				phy-connection-type = "2500base-x";
 				sleep = <&rcpm 0x20000000>;
 			};