rk3399-gru-kevin: issues on bringup

[Alper Nebi Yasak]

Hi Simon, Marty,

I'm interested in getting U-Boot to work with Kevin as well, but don't 
have a Servo (or the willingness to open up the case yet), so I've been 
trying to boot from depthcharge as in README.chromium-chainload.

I don't have a way to see serial output and I see no other signs of 
life. Can you give me a tested configuration that immediately powers-off 
or reboots a Kevin so I can confirm what I'm doing works on the 
chainloading side? I mean I can boot Linux, but trying the same with 
U-Boot just gives me a blank screen even after accounting for a lot of 
things.

Meanwhile, I've wrote some code to automate making depthcharge partition 
images, and to enable the display on Kevin (and perhaps Bob). Since I 
don't know if chainloading works, I don't know if these are broken or 
not either. I'm unsure about sending untested patches to the list, so I 
put them up here if you want to take a look (and maybe test/fix them?):

https://github.com/alpernebbi/u-boot/tree/rk3399-gru-kevin/wip

They're not really things that'd make a non-booting Kevin boot, though. 
I hope at least some of it can be useful in some way.