armv8: lx2160: Add secure boot target and enable distro boot.

Adds esbc validate command for verification of MC and DPC
firmware, along with secure boot defconfig.

Also enable distro boot.

Signed-off-by: Udit Agarwal <udit.agarwal@nxp.com>
Signed-off-by: Peng Ma <peng.ma@nxp.com>
[PK: squash "enable DM support for SATA patch" & add maintainer]
Signed-off-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>