drm/komeda: Add missing of_node_get() call

komeda_pipeline_destroy has the matching of_node_put().

Fixes: 29e56aec ("drm/komeda: Add DT parsing")
Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com>
Reviewed-by: Ayan Kumar Halder <ayan.halder@arm.com>
[Rebased on the latest drm-misc-fixes]
Signed-off-by: Ayan Kumar Halder <ayan.halder@arm.com>
Link: https://patchwork.freedesktop.org/patch/325278/

Change-Id: I5fa2479d6cb3a77182f1a92833c1c0bca8668cb4