mtd: nand: fixup for fmr initialization of Freescale NAND controller

There was a bug for fmr initialization, which lead to  fmr was always 0x100
in fsl_elbc_chip_init() and caused FCM command timeout before calling
fsl_elbc_chip_init_tail(), now we initialize CWTO to maximum timeout value
and not relying on the setting of bootloader.

Signed-off-by: Shengzhou Liu <Shengzhou.Liu@freescale.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>