arm: armada: dts: Add clock to armada-ap80x uart1

The uart1 node was missing the 'clock-frequency' property. This meant
the driver for this device would fail at probe.
The clock for uart1 is fed from the same source as uart0 and is a fixed
200MHz clock. This is confirmed via documentation for the CN9130 SoC
and from the equivalent code in Linux at:
<linux>/arch/arm64/boot/dts/marvell/armada-ap80x.dtsi
where uart0 and uart1 share a common 'clocks' definition.

Signed-off-by: Hamish Martin <hamish.martin@alliedtelesis.co.nz>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/arch/arm/dts/armada-ap80x.dtsi b/arch/arm/dts/armada-ap80x.dtsi
index 8787a87..ab3c32e 100644
--- a/arch/arm/dts/armada-ap80x.dtsi
+++ b/arch/arm/dts/armada-ap80x.dtsi
@@ -181,7 +181,7 @@
 				reg-io-width = <1>;
 				clocks = <&ap_syscon 3>;
 				status = "disabled";
-
+				clock-frequency = <200000000>;
 			};
 
 			watchdog: watchdog@610000 {