mtd: nand: omap: fix omap_calculate_ecc_bch() for-loop error

 Fixes:  2c9f2365
 mtd: nand: omap: ecc.calculate: merge omap3_calculate_ecc_bch4 in omap_calculate_ecc_bch

 Fixes: 7bcd1dca
 mtd: nand: omap: ecc.calculate: merge omap3_calculate_ecc_bch8 in omap_calculate_ecc_bch

Cc: <stable@vger.kernel.org> # 3.13.x+
Signed-off-by: Ted Juan <ted.juan@gmail.com>
Acked-by: Pekon Gupta <pekon@ti.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>