[U-Boot] Fastboot gadget, v2

[Sebastian Andrzej Siewior]

This series contains a smaller version of the fastboot gadget. I removed
the flash/mmc/write to media part and re-add once I'm through with this
basic thing :)
This "basic" gadget supports the retrieval of variables (like serial
number), reboot functionality, download of binary data and booting them in
case the binary data is a bootable image.
I did not include the fastboot client in this series. Remy asked about
this. I could take it and stash it in tools if someone really wants this
to have. This would include the fastboot and libzipfile folder from
Andorid's system/core repository. An online version can be found at [0]. I
haven't seen the library somewhere else than Android. For basic testing,
the library could be excluded.

v1..v2:
  fixed all issues that came up so far, including:
  - s/andoir_img_get_kload/android_img_get_kload/ spotted by Mike
  - adjusted Copyright message to GPLv2 or later for f_fastboot.c and
    removed "change" comments.
  - removed two header files in example patch 3/3
  I believe that the "All rights reserved" problem got resolved.

[0] http://www.netmite.com/android/mydroid/system/core/

Sebastian