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>

Documentation/devicetree/bindings/arm/tegra/nvidia,tegra30-mc.txt

-NVIDIA Tegra30 MC(Memory Controller)
-
-Required properties:
-- compatible : "nvidia,tegra30-mc"
-- reg : Should contain 4 register ranges(address and length); see the
-  example below. Note that the MC registers are interleaved with the
-  SMMU registers, and hence must be represented as multiple ranges.
-- interrupts : Should contain MC General interrupt.
-
-Example:
-	memory-controller {
-		compatible = "nvidia,tegra30-mc";
-		reg = <0x7000f000 0x010
-		       0x7000f03c 0x1b4
-		       0x7000f200 0x028
-		       0x7000f284 0x17c>;
-		interrupts = <0 77 0x04>;
-	};