ARM: dts: imx6sll: correct sdma compatible

Correct sdma compatible since ecspi errata ERR009165 has been fixed
on i.mx6sll as i.mx6ul.
Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx6sll.dtsi

@@ -621,7 +621,7 @@ csi: csi@20e8000 {
 			};
 
 			sdma: dma-controller@20ec000 {
-				compatible = "fsl,imx6sll-sdma", "fsl,imx35-sdma";
+				compatible = "fsl,imx6sll-sdma", "fsl,imx6ul-sdma";
 				reg = <0x020ec000 0x4000>;
 				interrupts = <GIC_SPI 2 IRQ_TYPE_LEVEL_HIGH>;
 				clocks = <&clks IMX6SLL_CLK_IPG>,