drm/mcde: Fix refcount leak in mcde_dsi_bind

drm/mcde: Fix refcount leak in mcde_dsi_bind

Every iteration of for_each_available_child_of_node() decrements
the reference counter of the previous node. There is no decrement
when break out from the loop and results in refcount leak.
Add missing of_node_put() to fix this.

Fixes: b54b2b95e2dd ("drm/mcde: Add new driver for ST-Ericsson MCDE")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220525115411.65455-1-linmq006@gmail.com