mtd: fsl_elbc_nand: fix jffs2 problem after NAND-flash image record in u-boot

This patch should fix the following problem:
 1. the  jffs2-image update in the u-boot was ok
 2. first restart and first mount of the NAND-flash-partition was also ok
 3. before the restart of controller there are no any activity on NAND-flash except of the jffs2_gcd_mtdX-process ...
 4. BUT after the second restart the NAND-flash-partition could not be really used after the second mount,
    dmesg filled with messages:
...
jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x03ce0000: 0xc0ff instead
jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at 0x03d00000: 0xc0ff instead
....
Just for for info:
the behaviour observed on mpc8313-based board with the large-page NAND.
The only activity on NAND-flash was the garbage collector process, that looks for CLEANMARKER-nodes

As Scott said it was broken by commit 3ab8f2a2

Signed-off-by: Sergej Stepanov <Sergej.Stepanov@ids.de>
--

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>