mtd: Blackfin NFC: fix build error after nand_scan_ident() change

Seems some patches got out sync when being merged.  The Blackfin NFC
driver was updated to use nand_scan_ident(), but it missed the change
where nand_scan_ident() now takes 3 arguments.  So update this driver
to fix build failures.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>