hwmon: (adt7470) Fix warning on module removal

When removing the adt7470 module, a warning might be printed:

do not call blocking ops when !TASK_RUNNING; state=1
set at [<ffffffffa006052b>] adt7470_update_thread+0x7b/0x130 [adt7470]

This happens because adt7470_update_thread() can leave the kthread in
TASK_INTERRUPTIBLE state when the kthread is being stopped before
the call of set_current_state(). Since kthread_exit() might sleep in
exit_signals(), the warning is printed.
Fix that by using schedule_timeout_interruptible() and removing
the call of set_current_state().
This causes TASK_INTERRUPTIBLE to be set after kthread_should_stop()
which might cause the kthread to exit.

Reported-by: Zheyu Ma <[e-mail]>
Fixes: 93cacfd41f82 (hwmon: (adt7470) Allow faster removal)
Signed-off-by: Armin Wolf <[e-mail]>
Tested-by: Zheyu Ma <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Guenter Roeck <[e-mail]>

drivers/hwmon/adt7470.c

···
 #include <linux/log2.h>
 #include <linux/kthread.h>
 #include <linux/regmap.h>
+#include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/util_macros.h>
 
···
 		adt7470_read_temperatures(data);
 		mutex_unlock(&data->lock);
 
-		set_current_state(TASK_INTERRUPTIBLE);
 		if (kthread_should_stop())
 			break;
 
-		schedule_timeout(msecs_to_jiffies(data->auto_update_interval));
+		schedule_timeout_interruptible(msecs_to_jiffies(data->auto_update_interval));
 	}
 
 	return 0;