ARM: dts: Add generic compatible for omap sdma instances

We need this to pass auxdata to all the sdma instances.

Cc: devicetree@vger.kernel.org
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Vinod Koul <vkoul@kernel.org>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Tested-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/dra7-l4.dtsi

@@ -212,7 +212,7 @@ SYSC_OMAP2_SOFTRESET |
 			ranges = <0x0 0x56000 0x1000>;
 
 			sdma: dma-controller@0 {
-				compatible = "ti,omap4430-sdma";
+				compatible = "ti,omap4430-sdma", "ti,omap-sdma";
 				reg = <0x0 0x1000>;
 				interrupts = <GIC_SPI 7 IRQ_TYPE_LEVEL_HIGH>,
 					     <GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>,

arch/arm/boot/dts/omap4-l4.dtsi

@@ -160,7 +160,7 @@ SYSC_OMAP2_SOFTRESET |
 			ranges = <0x0 0x56000 0x1000>;
 
 			sdma: dma-controller@0 {
-				compatible = "ti,omap4430-sdma";
+				compatible = "ti,omap4430-sdma", "ti,omap-sdma";
 				reg = <0x0 0x1000>;
 				interrupts = <GIC_SPI 12 IRQ_TYPE_LEVEL_HIGH>,
 					     <GIC_SPI 13 IRQ_TYPE_LEVEL_HIGH>,

arch/arm/boot/dts/omap5-l4.dtsi

@@ -237,7 +237,7 @@ SYSC_OMAP2_SOFTRESET |
 			ranges = <0x0 0x56000 0x1000>;
 
 			sdma: dma-controller@0 {
-				compatible = "ti,omap4430-sdma";
+				compatible = "ti,omap4430-sdma", "ti,omap-sdma";
 				reg = <0x0 0x1000>;
 				interrupts = <GIC_SPI 12 IRQ_TYPE_LEVEL_HIGH>,
 					     <GIC_SPI 13 IRQ_TYPE_LEVEL_HIGH>,