[Yaffs] Fix for mkyaffs2image utility

Hi,

This patch intends to address the issue of no file appears in a mounted
NAND partition which is written with yaffs2 image created by the
mkyaffs2image utility using nandwrite command. The patch applies only to
the mkyaffs2image.c file. The main problem was that mkyaffs2image was
writing YAFFS2 OOB data into the OOB area that the MTD driver uses for
ECC. Therefore we need to leave room inside the OOB yaffs2 image space
for data ECC. This is achieved by introducing a new optional parameter
called oob_ecc_size to specify the size of data ECC (e.g. for 2k
page/64bytes OOB, this data ECC is 14 bytes). The patch will copy the
OOB Tags into the OOB space starting at position oob_ecc_size. Please
also note that the default behavior of mkyaffs2image is not changed and
the nandwrite command to work with this patch is: nandwrite -a -o
MTD_DEVICE INPUTFILE.


Best Regards,
Vu Tran