ath79: fix OCEDO Koala ethernet configuration

The OCEDO Koala has incorrect PLL settings which result in ~3% packet
loss on ethernet connections.

Also omit the gmac-configuration as it's incorrect too.

Signed-off-by: David Bauer <mail@david-bauer.net>

target/linux/ath79/dts/qca9558_ocedo_koala.dts

@@ -156,15 +156,5 @@
 	phy-handle = <&phy5>;
 	phy-mode = "rgmii-rxid";
 
-	pll-data = <0xae000000 0xa0000101 0xa0001313>;
-
-	gmac-config {
-		device = <&gmac>;
-
-		rxdv-delay = <3>;
-		rxd-delay = <3>;
-		txen-delay = <0>;
-		txd-delay = <0>;
-		rgmii-enabled = <1>;
-	};
+	pll-data = <0x8e000000 0x80000101 0x80001313>;
 };