powerpc/85xx: Reserve a partition of NOR flash for QE ucode firmware

Due to the partition of JFFS2 overlaps with QE ucode firmware, So JFFS2
will break QE ucode. Shrink JFFS2's partition to reserve the space of
QE ucode firmware.

Signed-off-by: Jiucheng Xu <Jiucheng.Xu@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>