msm: camera: Change OV2720 exposure setting

When sensor is changed from one mode to another, Validate
coarse integration time and stretch frame length line if
needed. This is to ensure that coarse integration time is
always less than frame length lines.

Change-Id: I7c06e7d1d143d299a6203c56fad351e8cad2f5a1
Signed-off-by: Sreesudhan Ramakrish Ramkumar <srramku@codeaurora.org>