platform/chrome: wilco_ec: Fix unreleased lock in event_read()

When copying an event to userspace failed, the event queue
lock was never released. This fixes that.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Nick Crews <ncrews@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

drivers/platform/chrome/wilco_ec/event.c

@@ -342,7 +342,7 @@ static ssize_t event_read(struct file *filp, char __user *buf, size_t count,
 				 struct ec_event_entry, list);
 	n_bytes_written = entry->size;
 	if (copy_to_user(buf, &entry->event, n_bytes_written))
-		return -EFAULT;
+		n_bytes_written = -EFAULT;
 	list_del(&entry->list);
 	kfree(entry);
 	dev_data->num_events--;