ath79: fix 10 Mbit PLL data for UniFi AC

Fix the PLL register value for 10 Mbit/s link modes on the UniFi AC Lite
/ Mesh / LR. Otherwise, 10 Mbit/s links do not transfer data.

Signed-off-by: David Bauer <mail@david-bauer.net>
(cherry picked from commit 956407292d)

target/linux/ath79/dts/qca9563_ubnt_unifiac-lite.dtsi

@@ -24,4 +24,6 @@
 	mtd-mac-address = <&art 0x0>;
 	phy-mode = "sgmii";
 	phy-handle = <&phy4>;
+
+	pll-data = <0x03000000 0x00000101 0x00001313>;
 };