[JFFS2] Remove unneeded ifdefs from jffs2_fs_i.h

We certainly don't need the check for Linux version > 2.5.2, and in fact
we can also live without the __ECOS check, since we can just add it back
in the eCos git tree which is automatically derived from the Linux fs/jffs2
subdirectory in the upstream git tree.

Signed-off-by: Michal Piotrowski <michal.k.k.piotrowski@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>