msm: camera: isp: Update unlink handling to avoid race

Expire timer after destroying workqueues so that we
do not refer to watchdog timer while the link is
getting unlinked from session handle.

CRs-Fixed: 2585098
Change-Id: Ife2450ae66bd52ec704ac7d593b2daaeb20ba54d
Signed-off-by: Vikram Sharma <vikramsa@codeaurora.org>