EDAC, fsl_ddr: Add support for little endian

Get endianness from device tree. Both big endian and little endian are
supported. Default to big endian for backwards compatibility to MPC85xx.

Signed-off-by: York Sun <york.sun@nxp.com>
Acked-by: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: morbidrsa@gmail.com
Cc: oss@buserror.net
Cc: stuart.yoder@nxp.com
Link: http://lkml.kernel.org/r/1470779760-16483-7-git-send-email-york.sun@nxp.com
Signed-off-by: Borislav Petkov <bp@suse.de>

Documentation/devicetree/bindings/memory-controllers/fsl/ddr.txt

@@ -0,0 +1,29 @@
+Freescale DDR memory controller
+
+Properties:
+
+- compatible	: Should include "fsl,chip-memory-controller" where
+		  chip is the processor (bsc9132, mpc8572 etc.), or
+		  "fsl,qoriq-memory-controller".
+- reg		: Address and size of DDR controller registers
+- interrupts	: Error interrupt of DDR controller
+- little-endian	: Specifies little-endian access to registers
+		  If omitted, big-endian will be used.
+
+Example 1:
+
+	memory-controller@2000 {
+		compatible = "fsl,bsc9132-memory-controller";
+		reg = <0x2000 0x1000>;
+		interrupts = <16 2 1 8>;
+	};
+
+
+Example 2:
+
+	ddr1: memory-controller@8000 {
+		compatible = "fsl,qoriq-memory-controller-v4.7",
+				"fsl,qoriq-memory-controller";
+		reg = <0x8000 0x1000>;
+		interrupts = <16 2 1 23>;
+	};