[RFC] fs: add support for SquashFS

[Yegor Yefremov]

On Thu, Feb 11, 2016 at 3:56 PM,  <yegorslists at googlemail.com> wrote:
> From: Yegor Yefremov <yegorslists at googlemail.com>
>
> Signed-off-by: Yegor Yefremov <yegorslists at googlemail.com>

This is a first attempt to add SqaushFS to Barebox. The port is still
not fully functional, but it is possible to read files.

TODO:

1. improve directory listing: for now only root directory can be listed
2. support symlinks
3. implement freeing allocated structures on routine exit
4. remove Linux related stuff like spinlocks, wait etc.
5. add other decompressors (Gzip etc.)

Yegor