msm: thermal: Add support in KTM to export sensor information

Add support in KTM to export thermal sensor information
through sysfs interface /sys/module/msm_thermal/sensor_info.
Currently exposes sensor type, sensor name, sensor alias
and sensor scaling factor. The information is exported in
the format <sensor_type>:<sensor_name>:<sensor_alias>:
<sensor_scaling_factor> with a space separating each
sensor information.

Change-Id: I4fa2c08a68db17a33e0122fb3bed2f00b8a00711
Signed-off-by: Shiju Mathew <shijum@codeaurora.org>