Switching back to JFFS2 for 11.3.0 XO-1

[Daniel Drake]

Hi,

Unfortunately I haven't made enough progress on the XO-1 ubifs issues
so I'm planning to drop us back to JFFS2 for the first release
candidate of 11.3.0.
ubifs still remains as a very easy build customisation.

The main outstanding problems are that we have some systems which fail
to boot, and that our own partitioning overhead plus the unavoidable
ubifs overhead is really a bit much (over 75mb I think).

Progress is being made on both issues, but won't be ready in time for
the freeze for the release.

Daniel