u-boot update for ast2600

[Joel Stanley]

Hello OpenBMCers who care about u-boot,

I've updated OpenBMC u-boot tree to use ASPEED's latest SDK,
v00.03.03. I've also applied the series to support for FIT
verification including use of the HACE to perform SHA hashing that
I've been working on with Klaus. The bump is here:

 https://gerrit.openbmc-project.xyz/c/openbmc/openbmc/+/42502

I've sent a set of fixes backported from mainline to ASPEED for
merging in a future SDK release:

 https://github.com/AspeedTech-BMC/u-boot/pull/7

We still have a number of patches carried that are specific to
OpenBMC, and of course the new FIT and HACE support.

My focus is on supporting u-boot on ast2600 with eMMC. I test this
mostly in Qemu with Cédric's aspeed-6.0 branch:

https://github.com/shenki/qemu-boot-test/

I do  run u-boot from NOR on the ast2600a2 evb I have, but I would
encourage testing from others if they care about this platform setup
as it gets much less attention from me.

Cheers,

Joel