To support loading a 32-bit OS, the execution state will change from
AArch64 to AArch32 when jumping to kernel.

The architecture information will be got through checking FIT image,
then U-Boot will load 32-bit OS or 64-bit OS automatically.
Signed-off-by: NEbony Zhu <ebony.zhu@nxp.com>
Signed-off-by: NAlison Wang <alison.wang@nxp.com>
Signed-off-by: NChenhui Zhao <chenhui.zhao@nxp.com>
Reviewed-by: NYork Sun <york.sun@nxp.com>