msm: thermal: Prolong KTM mitigation till thermal-engine takesover

KTM stops the boot time mitigation during late init
and thermal engine takes over the mitigation only after
a delay.

Modify KTM to prolong the boot time mitigation till
thermal-engine sends a disable command. This ensures a
safe handover.

CRs-Fixed: 1007266
Change-Id: Icb876f16cac9471c523f3ef5b5fd3ede9d5d597c
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>