media: hi846: fix usage of pm_runtime_get_if_in_use()

pm_runtime_get_if_in_use() does not only return nonzero values when
the device is in use, it can return a negative errno too.

And especially during resuming from system suspend, when runtime pm
is not yet up again, -EAGAIN is being returned, so the subsequent
pm_runtime_put() call results in a refcount underflow.

Fix system-resume by handling -EAGAIN of pm_runtime_get_if_in_use().
Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
Fixes: e8c08826 ("media: i2c: add driver for the SK Hynix Hi-846 8M pixel camera")
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

drivers/media/i2c/hi846.c

@@ -1353,7 +1353,8 @@ static int hi846_set_ctrl(struct v4l2_ctrl *ctrl)
 					 exposure_max);
 	}
 
-	if (!pm_runtime_get_if_in_use(&client->dev))
+	ret = pm_runtime_get_if_in_use(&client->dev);
+	if (!ret || ret == -EAGAIN)
 		return 0;
 
 	switch (ctrl->id) {