drm/tilcdc: panel: Add missing of_node_put

This commit adds the missing calls to of_node_put to release the node
that's currently held by the of_get_child_by_name() call in the panel
info parsing code.

Tested-by: Darren Etheridge <detheridge@ti.com>
Tested-by: Johannes Pointner <johannes.pointner@br-automation.com>
Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Dave Airlie <airlied@redhat.com>