mtd: atmel_nand: NFC: fix mtd_nandbiterrs.ko test fail when using sram write

When enable NFC sram write, it will failed the mtd_nandbiterrs.ko test.

As in driver's nfc_sram_write_page(), if ops->mode equal to MTD_OSP_RAW,
driver assumes the data buffer contains one page data and one oob data
followed. And driver will write the page data and oob data to nand.

But this is wrong implementation. Since the data buffer don't contains the
oob data to write. We should write the chip->oob_poi to nand's oob.

So this patch fix it by writing the oob data from chip->oob_poi.

Signed-off-by: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>