ARM64: zynqmp: Add missing earlycon for ep108

Just sync between version. Others zynqmp boards have this setup.
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
Reviewed-by: NSimon Glass <sjg@chromium.org>

arch/arm/dts/zynqmp-ep108.dts

@@ -28,6 +28,7 @@
 	};
 
 	chosen {
+		bootargs = "earlycon";
 		stdout-path = "serial0:115200n8";
 	};