ENGR000234991 MX6DL/ARD: Two boards met kernel dump during boot up

The issue is caused by DDR script changed io pads to DDR differential mode
but forget to do the calibration data update.

This patch updated the DDR script on MX6DL ARD board based on
the commit on the ddr-scripts-rel:
53121e0 Updated MX6DL and MX6DQ ARD and SabreSD scripts with new
calibration values for IO pads set to differential mode;

Signed-off-by: Jason Liu <r64343@freescale.com>