dt-bindings: arm: tegra: Remove duplicated Tegra30+ MC binding

There are two bindings for the same Memory Controller. One of the bindings
became obsolete long time ago and probably was left unnoticed, remove it
for consistency.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>