arm: zynq: Remove earlycon from bootargs

Earlyconsole is used for early kernel debugging that's why this option
shouldn't be enabled by default.
Earlyconsole is partially copying the part of the bootlog after
"bootconsole [uart0] disabled".

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/arm/boot/dts/zynq-zed.dts

@@ -29,7 +29,7 @@
 	};
 
 	chosen {
-		bootargs = "earlycon";
+		bootargs = "";
 		stdout-path = "serial0:115200n8";
 	};