lx2160a : Add emmc in boot_targets environment variable

Add emmc in supported boot_targets and
Add bootcmd environment variable for emmc boot.

Signed-off-by: Meenakshi Aggarwal <meenakshi.aggarwal@nxp.com>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>
3 files changed