thermal/debugfs: Create records for cdev states as they get used

Because thermal_debug_cdev_state_update() only creates a duration record
for the old state of a cooling device, if its new state is used for the
first time, there will be no record for it and cdev_dt_seq_show() will
not print the duration information for it even though it contains code
to compute the duration value in that case.

Address this by making thermal_debug_cdev_state_update() create a
duration record for the new state if there is none.

Fixes: 755113d7 ("thermal/debugfs: Add thermal cooling device debugfs information")
Reported-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Tested-by: Lukasz Luba <lukasz.luba@arm.com>

drivers/thermal/thermal_debugfs.c

@@ -435,6 +435,14 @@ void thermal_debug_cdev_state_update(const struct thermal_cooling_device *cdev,
 	}
 
 	cdev_dbg->current_state = new_state;
+
+	/*
+	 * Create a record for the new state if it is not there, so its
+	 * duration will be printed by cdev_dt_seq_show() as expected if it
+	 * runs before the next state transition.
+	 */
+	thermal_debugfs_cdev_record_get(thermal_dbg, cdev_dbg->durations, new_state);
+
 	transition = (old_state << 16) | new_state;
 
 	/*