arm64: zynqmp: Assign TSU clock frequency for KV and KD boards

Set TSU clock frequency as 250MHz (minimum when running at 1G) on
KV and KD carrier cards to allow PTP functionality.

Signed-off-by: Harini Katakam <harini.katakam@amd.com>
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/4b758d503ef545e4d25d3930b0eb0793f1c415d2.1688992653.git.michal.simek@amd.com
diff --git a/arch/arm/dts/zynqmp-sck-kv-g-revB.dts b/arch/arm/dts/zynqmp-sck-kv-g-revB.dts
index 96a5121..0ac2086 100644
--- a/arch/arm/dts/zynqmp-sck-kv-g-revB.dts
+++ b/arch/arm/dts/zynqmp-sck-kv-g-revB.dts
@@ -152,6 +152,7 @@
 	pinctrl-0 = <&pinctrl_gem3_default>;
 	phy-handle = <&phy0>;
 	phy-mode = "rgmii-id";
+	assigned-clock-rates = <250000000>;
 
 	mdio: mdio {
 		#address-cells = <1>;