Input: twl6040-vibra - add missing of_node_put

We should drop reference to twl6040_core_node device_node once we are done
using it.

Signed-off-by: Libo Chen <libo.chen@huawei.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>