dmaengine: dw_dma: add Device Tree probing capability

SPEAr platforms now support DT and so must convert all drivers to support DT.
This patch adds DT probing support for Synopsys DMA controller and updates its
documentation too.

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
diff --git a/Documentation/devicetree/bindings/dma/snps-dma.txt b/Documentation/devicetree/bindings/dma/snps-dma.txt
new file mode 100644
index 0000000..c0d85db
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/snps-dma.txt
@@ -0,0 +1,17 @@
+* Synopsys Designware DMA Controller
+
+Required properties:
+- compatible: "snps,dma-spear1340"
+- reg: Address range of the DMAC registers
+- interrupt-parent: Should be the phandle for the interrupt controller
+  that services interrupts for this device
+- interrupt: Should contain the DMAC interrupt number
+
+Example:
+
+	dma@fc000000 {
+		compatible = "snps,dma-spear1340";
+		reg = <0xfc000000 0x1000>;
+		interrupt-parent = <&vic1>;
+		interrupts = <12>;
+	};