msm: dcvs: add thermal control

Add capability to read the sensor data and report the temperature of
a core to the TZ.

Note that this was done earlier whenever a frequency update was done,
instead create a delayed workqueue per core. Also create a attribute
that controls the rate of thermal update per core.

If that attribute is not set use 60seconds as the default update rate.
If it is less than one second, default to using one second.

Change-Id: I3cfee309771274674aec28545d0bf69b3d906fe1
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>