irqchip: armada-370-xp: Move the devicetree binding documentation

Move the devicetree binding documentation to the interrupt-controller
directory, where it belongs.

Reviewed-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Link: https://lkml.kernel.org/r/1400457737-1617-1-git-send-email-ezequiel.garcia@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

Documentation/devicetree/bindings/interrupt-controller/marvell,armada-370-xp-mpic.txt

@@ -0,0 +1,38 @@
+Marvell Armada 370, 375, 38x, XP Interrupt Controller
+-----------------------------------------------------
+
+Required properties:
+- compatible: Should be "marvell,mpic"
+- interrupt-controller: Identifies the node as an interrupt controller.
+- msi-controller: Identifies the node as an PCI Message Signaled
+  Interrupt controller.
+- #interrupt-cells: The number of cells to define the interrupts. Should be 1.
+  The cell is the IRQ number
+
+- reg: Should contain PMIC registers location and length. First pair
+  for the main interrupt registers, second pair for the per-CPU
+  interrupt registers. For this last pair, to be compliant with SMP
+  support, the "virtual" must be use (For the record, these registers
+  automatically map to the interrupt controller registers of the
+  current CPU)
+
+Optional properties:
+
+- interrupts: If defined, then it indicates that this MPIC is
+  connected as a slave to another interrupt controller. This is
+  typically the case on Armada 375 and Armada 38x, where the MPIC is
+  connected as a slave to the Cortex-A9 GIC. The provided interrupt
+  indicate to which GIC interrupt the MPIC output is connected.
+
+Example:
+
+        mpic: interrupt-controller@d0020000 {
+              compatible = "marvell,mpic";
+              #interrupt-cells = <1>;
+              #address-cells = <1>;
+              #size-cells = <1>;
+              interrupt-controller;
+              msi-controller;
+              reg = <0xd0020a00 0x1d0>,
+                    <0xd0021070 0x58>;
+        };