msm: thermal: Update KTM thresholds via debugfs interface

Update KTM mitigation threshold and threshold clear
dynamically via debugfs interface. Below is an example
to update mx retention thresholds.
 echo 60 > /sys/kernel/debug/msm_thermal/config/mx/thresh_degc
 echo 50 > /sys/kernel/debug/msm_thermal/config/mx/thresh_clr_degc
 echo 1 > /sys/kernel/debug/msm_thermal/config/mx/update
 echo -n update > /sys/kernel/debug/msm_thermal/config/data

Change-Id: Ia51def4616aee2140279ab0757476733270309db
Signed-off-by: Shiju Mathew <shijum@codeaurora.org>