dt: bindings: Move tegra20-emc binding to memory-controllers directory

Move tegra20-emc binding to the memory-controllers directory for
consistency with the other Tegra memory bindings.

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

diff --git a/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra20-emc.txt b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt
similarity index 100%
rename from Documentation/devicetree/bindings/arm/tegra/nvidia,tegra20-emc.txt
rename to Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt