msm: camera: cci: Enhance burst read timing

In burst read flow, we need to wait CCI irq
once one set data is read, but the fifo may has
new data what can be read immediately and don't
need to wait the irq. This change also optimize
the irq processing, we can reset irq mask first,
then process the irq status, it can avoids some
timing issue, e.g. the read context runs too
quickly, then read context enable the read
threshold bit in irq mask1, but irq context runs
late, then irq context clear the read threshold,
then we can't receive read threshold again.

CRs-Fixed: 2995920
Change-Id: I8acfadf07b95782725bf4bf8b05b88789874c1da
Signed-off-by: Depeng Shao <depengs@codeaurora.org>