msm: camera: isp: fix the livesnap shot issue

The livesnap shot is not working since the isp driver does not reset
the framedrop period correctly. This change make sure the isp driver
will reset this period correctly

Change-Id: I7cb642c46a0447ba5b1e4e8929a1d614ccb6d04d
Signed-off-by: Jing Zhou <jzhou70@codeaurora.org>