mei: prevent unloading mei hw modules while the device is opened.

chrdev_open() increases reference counter on cdev->owner. Instead of
assigning the owner to mei subsystem, the owner has to be set to the
underlaying HW module (mei_me or mei_txe), so once the device is opened
the HW module cannot be unloaded.

Cc: <stable@vger.kernel.org> #3.17+
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/main.c

@@ -682,7 +682,7 @@ int mei_register(struct mei_device *dev, struct device *parent)
 	/* Fill in the data structures */
 	devno = MKDEV(MAJOR(mei_devt), dev->minor);
 	cdev_init(&dev->cdev, &mei_fops);
-	dev->cdev.owner = mei_fops.owner;
+	dev->cdev.owner = parent->driver->owner;
 
 	/* Add the device */
 	ret = cdev_add(&dev->cdev, devno, 1);