kernel: msm8974 tsens ftrace events

Added ftrace events tsens_read, tsens_threshold_hit, and
tsens_threshold_clear. Added function calls to said events
when relevant.

Change-Id: If98fe1e5a83943bb7cf3d1492c46df73fa6eeec1
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>