docs: thermal: time_in_state is displayed in msec and not usertime

The sysfs stats for cooling devices shows the time_in_state in msec,
remove the unwanted usertime comment.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/d5461bdf9ab6b6fee7f28f538582edbb426aa077.1605004905.git.viresh.kumar@linaro.org

Documentation/driver-api/thermal/sysfs-api.rst

@@ -654,8 +654,7 @@ stats/time_in_state_ms:
 	The amount of time spent by the cooling device in various cooling
 	states. The output will have "<state> <time>" pair in each line, which
 	will mean this cooling device spent <time> msec of time at <state>.
-	Output will have one line for each of the supported states.  usertime
-	units here is 10mS (similar to other time exported in /proc).
+	Output will have one line for each of the supported states.
 	RO, Required