dt-bindings: move various RNG bindings to rng/ directory

Bindings are supposed to be organized by device class/function. Move
bindings for various RNGs to rng/ binding directory.

Signed-off-by: Rob Herring <robh@kernel.org>

diff --git a/Documentation/devicetree/bindings/crypto/samsung,exynos-rng4.txt b/Documentation/devicetree/bindings/rng/samsung,exynos4-rng.txt
similarity index 100%
rename from Documentation/devicetree/bindings/crypto/samsung,exynos-rng4.txt
rename to Documentation/devicetree/bindings/rng/samsung,exynos4-rng.txt

diff --git a/Documentation/devicetree/bindings/sparc_sun_oracle_rng.txt b/Documentation/devicetree/bindings/rng/sparc_sun_oracle_rng.txt
similarity index 100%
rename from Documentation/devicetree/bindings/sparc_sun_oracle_rng.txt
rename to Documentation/devicetree/bindings/rng/sparc_sun_oracle_rng.txt