tty: xuartps: Update copyright information

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/xilinx_uartps.c

 /*
  * Xilinx PS UART driver
  *
- * 2011 (c) Xilinx Inc.
+ * 2011 - 2013 (C) Xilinx Inc.
  *
  * This program is free software; you can redistribute it
  * and/or modify it under the terms of the GNU General Public