media: vpif_capture: fix OF node reference imbalance

media: vpif_capture: fix OF node reference imbalance

The driver reuses the OF node of the parent device but fails to take
another reference to balance the one dropped by the platform bus code
when unbinding the parent and releasing the child devices.

Fix this by using the intended helper for reusing OF nodes.

Fixes: 4a5f8ae50b66 ("[media] davinci: vpif_capture: get subdevs from DT when available")
Cc: stable@vger.kernel.org	# 4.13
Cc: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>