drivers: of-thermal: Group sensor related information

Sensor related information like the sensor callback ops and sensor data
live in the thermal zone data structure along with other parameters.
These meta data will be used by the sibling thermal zones and it will be
shared across thermal zones.

Move the sensor related information into a separate data structure, which
will be referenced by the thermal zone.

Change-Id: Iace7972820e7e7f9ca0d7e9610319256747760c5
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>