thermal: msm8960_tsens: Fix setting mode for disabled sensors

Thermal driver in kernel currently requires the main sensor
to perform mitigation. Disable all the auxiliary sensors
and update the mode of the main sensor as being enabled during
TSENS init.

Round the converted temperature to the nearest degree.
Remove unwanted register reads added for debug and reference
to magic numbers in the code.

Change-Id: Id5652ba16f9adb462dc61266600f394901eee194
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>