armv8: lx2160a: Updates secure boot headers offset

Updates the secure boot headers offsets of Kernel and other
firmware images for SD and XSPI boot sources used by
esbc_validate command.

Signed-off-by: Priyanka Singh <priyanka.singh@nxp.com>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>