[Yaffs] yaffs gets xattrib support

Hi All

Yesterday I checked in xattrib support. This is available through both Linux
and Yaffs Direct.

The xattribs are stored in unused space in the object header which limits the
amount of xattrib info that can be stored to approximately (page_size - 512).
Thus with 2k page NAND you'll get approx 1500 bytes of xattrib. From my
limited understanding of how xattribs are used, this should be enough for
most applications (SELinux uses around 200 bytes).

To enable xattrib support in Linux you will need to set CONFIG_YAFFS_XATTRIB.

For Yaffs Direct you will need to set param.enableXattrib=1;


Any feedback welcome.

-- Charles