msm: camera: ope: Fix the length check for debug buffer

Debug buffer passed by UMD is smaller than the required
size to collect the replay dump.

Corrected the debug buffer length check and don't dump
replay data incase of flush.

CRs-Fixed: 2629735
Change-Id: I07bc3c9585ab8ad00cd858ecd807e473075795aa
Signed-off-by: Alok Chauhan <alokc@codeaurora.org>