msm: thermal: Update to speed up bootup time

Update KTM driver to remove flush_scheduled_work that
would introduce bootup delay. This patch replaces
cancel_delayed_work with cancel_delayed_work_sync
to cancel a delayed work.

CRs-Fixed: 647439
Change-Id: Ie81278ca3a7a58f8f46463f7149b512bd07cbcbc
Signed-off-by: Shiju Mathew <shijum@codeaurora.org>