ARM: dts: add generic DMA device tree binding for mxs-dma

Add generic DMA device tree binding for mxs-dma.  The changes include:

 * Add channel interrupts into DMA controller nodes
 * Add properties '#dma-cells' and 'dma-channels' for DMA controller nodes
 * And properties 'dmas' and 'dma-names' for DMA client nodes
 * Update mxs-dma device tree binding doc

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/arch/arm/boot/dts/imx6qdl.dtsi b/arch/arm/boot/dts/imx6qdl.dtsi
index 06ec460..59e970f 100644
--- a/arch/arm/boot/dts/imx6qdl.dtsi
+++ b/arch/arm/boot/dts/imx6qdl.dtsi
@@ -65,9 +65,13 @@
 		interrupt-parent = <&intc>;
 		ranges;
 
-		dma-apbh@00110000 {
+		dma_apbh: dma-apbh@00110000 {
 			compatible = "fsl,imx6q-dma-apbh", "fsl,imx28-dma-apbh";
 			reg = <0x00110000 0x2000>;
+			interrupts = <0 13 0x04>, <0 13 0x04>, <0 13 0x04>, <0 13 0x04>;
+			interrupt-names = "gpmi0", "gpmi1", "gpmi2", "gpmi3";
+			#dma-cells = <1>;
+			dma-channels = <4>;
 			clocks = <&clks 106>;
 		};
 
@@ -83,6 +87,8 @@
 				 <&clks 150>, <&clks 149>;
 			clock-names = "gpmi_io", "gpmi_apb", "gpmi_bch",
 				      "gpmi_bch_apb", "per1_bch";
+			dmas = <&dma_apbh 0>;
+			dma-names = "rx-tx";
 			fsl,gpmi-dma-channel = <0>;
 			status = "disabled";
 		};