[U-Boot] u-boot FIT image support

[York Sun <yorksun@freescale.com>]

Simon,

I was doing an experiment to put the load address and entry address of Linux to
higher than 32-bit address. I found it is broken to process more than 32-bit
addresses. When I attempted to fix it, I was troubled by those code used for
both host and target, like common/image-fit.c. For example, to process 64-bit
address, the function

int fit_image_get_load(const void *fit, int noffset, ulong *load)

should be converted to

int fit_image_get_load(const void *fit, int noffset, uint64_t *load)

ulong is 64-bit for 64-bit target such as ARMv8, but it can be 32-bit on host.
If I use uint64_t, all related code in bootm and others need to change. Before I
go too far, I'd like to check if anyone has tried to enable this in FIT image.

#address-cells = <2>;

I can try to use uint64_t in place of ulong for all related code if that's
right. That will be a lot of change.

York