dt-bindings: move Calxeda bindings to appropriate subsystems

Move the Calxeda memory controller and PHY bindings to appropriate
subsystem directories.

Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: Kumar Gala <galak@codeaurora.org>

Documentation/devicetree/bindings/memory-controllers/calxeda-ddr-ctrlr.txt

@@ -0,0 +1,16 @@
+Calxeda DDR memory controller
+
+Properties:
+- compatible : Should be:
+  - "calxeda,hb-ddr-ctrl" for ECX-1000
+  - "calxeda,ecx-2000-ddr-ctrl" for ECX-2000
+- reg : Address and size for DDR controller registers.
+- interrupts : Interrupt for DDR controller.
+
+Example:
+
+	memory-controller@fff00000 {
+		compatible = "calxeda,hb-ddr-ctrl";
+		reg = <0xfff00000 0x1000>;
+		interrupts = <0 91 4>;
+	};