Add support for Synology DS414 and some related fixes

Quoted 11 lines · Phil Sutter

This patch series ultimately adds support for Synology DS414 NAS after a few fixes:
* Patches 1-3 and 5 fix various files for enabled debugging.
* Patch 4 updates the board porting guide in README file.
* Patches 6-8 hold crucial fixes necessary for DS414 support.
* Patches 9 and 10 contain the actual board support, split into a generic part for MV78230 SoC and a board specific part for clarity.
* Patch 11 adds a new command to deal with Synology specialties.

In case you would like me to split this into multiple series, just let me know and I will resend.

Very nice to see other Armada XP based boards getting supported in mainline U-Boot. I'm currently also working on a new XP board based on the MV78260. And stumbled over a few of the problems you have met in your Armada XP support as well.

Since I'm currently preparing a new patchset for all this, including the full DM SPL support as well, perhaps it would be best, if you base your MV78230 work in top of my new patches. I will send the new patches to the list later today. And will also publish a git branch for easier work with it. Since there are some dependencies with other patches as well.

BTW: With this work you should be able to drop all those "non-DM" patches from your series.

PS: Please keep Luka and me on Cc on all mvebu related patches.