drm/msm: Remove bad calls to of_node_put()

In add_components_mdp, we parse the endpoints in MDP output ports
using the helper for_each_endpoint_of_node(). Our function calls
of_node_put() on the endpoint node before we iterate over the
next one. This is already done by the helper, and results in
trying to decrement the refcount twice.

Remove the extra of_node_put calls. This fixes warnings seen when
we try to insert the driver as a module on IFC6410.

Signed-off-by: Archit Taneja <architt@codeaurora.org>