msm: thermal: Support a debugfs to control temperature logging

Support a new debug file system entry, which can enable
or disable temperature logging during kernel panic.

This logging is disabled by default. The below command
can be used to enable this temperature logging,
echo 'Y' > /sys/kernel/debug/msm_thermal/log_tsens_temperature

Change-Id: I4c78c1f21dba6ecf3c91b2ba6c731d8c44570dfb
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>