[BUG] hwmon: (adt7470) warning when removing the module

[Zheyu Ma]

I found a bug when removing the adt7470 module.

The following log can reveal it:

[   18.459479] ------------[ cut here ]------------
[   18.459852] do not call blocking ops when !TASK_RUNNING; state=1
set at [<ffffffffa006052b>] adt7470_update_thread+0x7b/0x130 [adt7470]
[   18.460857] WARNING: CPU: 7 PID: 365 at kernel/sched/core.c:9660
__might_sleep+0x96/0xb0
[   18.461523] Modules linked in: adt7470(-)
[   18.464568] RIP: 0010:__might_sleep+0x96/0xb0
[   18.472577] Call Trace:
[   18.472778]  <TASK>
[   18.472957]  exit_signals+0x2f/0x3b0
[   18.473251]  do_exit+0xcd/0x18c0
[   18.473534]  ? __mutex_unlock_slowpath+0x1b8/0x740
[   18.473927]  kthread_exit+0x42/0x60
[   18.474212]  ? adt7470_detect+0x140/0x140 [adt7470]
[   18.474622]  kthread+0x272/0x2e0
[   18.474885]  ? adt7470_detect+0x140/0x140 [adt7470]
[   18.475277]  ? kthread_blkcg+0xa0/0xa0
[   18.475601]  ret_from_fork+0x22/0x30
[   18.475901]  </TASK>

Regards,
Zheyu Ma