ARM: zynq: Fix incorrect reference to XM013 instead of XM011

Fix comment about targeted extension card. It was likely just c&p error.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/39e16e667aa8f132496092d4fa554935ddd5a55f.1606399500.git.michal.simek@xilinx.com

arch/arm/boot/dts/zynq-zc770-xm011.dts

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0+
 /*
- * Xilinx ZC770 XM013 board DTS
+ * Xilinx ZC770 XM011 board DTS
  *
  * Copyright (C) 2013-2018 Xilinx, Inc.
  */