[MTD] [NAND] Blackfin NFC Driver: mark bf5xx_nand_add_partition() as __devinit

The bf5xx_nand_add_partition() func is only called by __devinit functions,
so put it into the __devinit section as well

Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>