drm/meson: encoder_cvbs: Fix refcount leak in meson_encoder_cvbs_init

of_graph_get_remote_node() returns remote device nodepointer with
refcount incremented, we should use of_node_put() on it when done.
Add missing of_node_put() to avoid refcount leak.

Fixes: 318ba02c ("drm/meson: encoder_cvbs: switch to bridge with ATTACH_NO_CONNECTOR")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220601033927.47814-2-linmq006@gmail.com