[Yaffs] Checkin of 2.6 patches

I have just checked in Nick's 2.6.8.1 patches, plus some mods to make
compiling a little cleaner across versions.

Changes are to yaffs_fs.c and yaffs_mtdif.c.

See the following for changes;

http://www.aleph1.co.uk/cgi-bin/viewcvs.cgi/yaffs/yaffs_mtdif.c.diff?r1=1.9&r2=1.10
http://www.aleph1.co.uk/cgi-bin/viewcvs.cgi/yaffs/yaffs_fs.c.diff?r1=1.32&r2=1.33

Regards

-- Charles