[U-Boot-Custodians] Merge window and pull requests

[Eugen.Hristev at microchip.com]

Hello Tom,

Just to clarify the "merge window" policy:
Do you take PR for new boards after the RC1 tag of a release or we 
should wait for new boards/features until the next merge window ? 
(meaning you only take PR with fixes).
I saw that you are still merging many new things even after RC1 and just 
before the final release tag.
I am asking because I want to know whether I should send a PR with new 
features at any time or have to wait for next release.

Thanks !
Eugen