Fix and refactor mirroring config

It's probably a wrong idea to mix Prague-specific mirror config with
board config, so let's keep these around but somewhere else.

Also fix them so that they actually point to a place which works...

Change-Id: If844359798be0e8d63be4ca2c526344091c943a4
5 files changed
tree: f9c0b4db392a02f8f0d44ec8700d534a540d0c9e
  1. Config.in
  2. board/
  3. configs/
  4. external.desc
  5. external.mk
  6. package/