msm: thermal: Add support to read KTM thermal configuration

Add support in KTM to read thermal threshold
configurations through debugfs interface. Below
is the command to read KTM configuration from shell.

       cat /sys/kernel/debug/msm_thermal/config

Change-Id: I3ff937875e8b5136584ab10af75dbed71b1443ac
Signed-off-by: Shiju Mathew <shijum@codeaurora.org>