msm: camera: ope: Fix false hw hang detection

While preparing config packet at HW layer,
we are setting Ope request timer even before
processing command buffer and IO cfg. This is
leading to false hw hand detection.
Expectation is Ope request timer has to
start after req is submitted to HW.

CRs-Fixed: 2788900
Change-Id: Idd1420b2ee1aed4bfe947cf5617bbec9b39147d3
Signed-off-by: Shravya Samala <shravyas@codeaurora.org>