Add code to build the eMMC variant of the Colibri iMX6ULL, i.e. the
'Colibri iMX6ULL 1GB' which has a eMMC instead of the raw NAND used
on other SKUs.
Related-to: ELB-4056, ELB-4057
Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>