staging: media: tegra-video: slightly simplify cleanup on errors

of_node_put(node) does nothing if node == NULL, so it can be moved to the
cleanup section at the bottom.

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>