uboot-phytec

MLK-14366 mx6sllevk: Update board codes to align with v2016.03

Update mx6sll EVK board codes for features:
1. Add SD/MMC dynamical device detect.
2. Add wdog set for kernel.
3. Add mfgtool environments.
4. Modify SD/MMC environment offset.

Signed-off-by: Ye Li <ye.li@nxp.com>