mtd: msm_qpic_nand: reduce the number of ce

Command elements (ce) for both page read and page write can be
reduced for improving performance. This change improves throughput
by approximately 0.8 MBps.

Change-Id: Ie3171ebf553df6eebc97a9f5214d9c9ccb5e808f
Signed-off-by: Krishna Konda <kkonda@codeaurora.org>