armv8: ls1088ardb: Add distro boot support

Distro boot support gives flexibility to run distro RFS like Ubuntu
being deployed from SD card or SATA drive. If it fails to detect
external storage, fall back to qspi/sd boot.

Enable this by default in RDB's defconfig by selecting
CONFIG_DISTRO_DEFAULTS

Signed-off-by: Ashish Kumar <Ashish.Kumar@nxp.com>
Signed-off-by: Zhang Ying <zhangying@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>
3 files changed