[U-Boot] [ANN] U-Boot v2018.01-rc2 released

Hey all,

It's release day and v2018.01-rc2 is out. I'm mostly happy with the size of the changes here and I did remember to sync the defconfigs prior to tagging.

Once again, at this point, any changes that come in need to be clear fixes to a problem or Kconfig migrations that can be shown as correct. The exception is that I'm expecting another spin on the imx PR to fix some problems that are known there.

Things look on track for -rc3 on the 1st of January and release on the 8th. Thanks all!