msm: vidc: Add thermal mitigation feature

Thermal agent from userspace reports thermal level
value through sysfs node. Based on thermal levels,
video driver takes below action to avoid any further
overheating.
1. Normal thermal level(T0) is ignored.
2. Low(T1) or high(T2) thermal level is ignored for
   usecase running in nominal/svs clock whereas all
   video sessions are terminated for turbo usecase.
3. During critical(T3) thermal level, all video
   sessions are terminated.

Change-Id: I516761fc51e824b35957a85009de7f08b15d887c
Signed-off-by: Vikash Garodia <vgarodia@codeaurora.org>
Signed-off-by: Maheshwar Ajja <majja@codeaurora.org>