mei: nfc: mei_nfc_free has to be called under lock

nfc_nfc_free unlink clients from the device list
and has to be called under mei mutex

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Reviewed-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/nfc.c

@@ -469,7 +469,9 @@ static void mei_nfc_init(struct work_struct *work)
 	return;
 
 err:
+	mutex_lock(&dev->device_lock);
 	mei_nfc_free(ndev);
+	mutex_unlock(&dev->device_lock);
 
 	return;
 }