Currently, the space between kernel loading address and u-boot start address
is less than 512KB, smaller than u-boot size.  This is ok for normal booting,
because u-boot will relocate itself to higher memory address before loading the
kernel. But for mfgtool which pre-loads kernel and u-boot into memory, this causes overlap.

So need change the kernel loading address. Add 2MB offset to it. Because ARM64 kernel
has such requirement:
"arm64 requires the kernel image to placed TEXT_OFFSET bytes beyond a 2 MB aligned base“

Signed-off-by: Ye Li <ye.li@nxp.com>
Reviewed-by : Peng Fan <peng.fan@nxp.com>