media: davinci: vpif: fix unbalanced runtime PM enable

Make sure to disable runtime PM before returning on probe errors.

Fixes: 479f7a11

 ("[media] davinci: vpif: adaptions for DT support")
Cc: stable@vger.kernel.org
Cc: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>