arm64: zynqmp: Fix serial compatible string

Based on commit 65a2c14d ("dt-bindings: serial: convert Cadence UART
bindings to YAML") compatible string should look like differently that's
why fix it to be aligned with dt binding.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/89b36e0a6187cc6b05b27a035efdf79173bd4486.1628240307.git.michal.simek@xilinx.com

arch/arm64/boot/dts/xilinx/zynqmp.dtsi

@@ -786,7 +786,7 @@ ttc3: timer@ff140000 {
 		};
 
 		uart0: serial@ff000000 {
-			compatible = "cdns,uart-r1p12", "xlnx,xuartps";
+			compatible = "xlnx,zynqmp-uart", "cdns,uart-r1p12";
 			status = "disabled";
 			interrupt-parent = <&gic>;
 			interrupts = <0 21 4>;
@@ -796,7 +796,7 @@ uart0: serial@ff000000 {
 		};
 
 		uart1: serial@ff010000 {
-			compatible = "cdns,uart-r1p12", "xlnx,xuartps";
+			compatible = "xlnx,zynqmp-uart", "cdns,uart-r1p12";
 			status = "disabled";
 			interrupt-parent = <&gic>;
 			interrupts = <0 22 4>;