ARM: dts: imx6sl: Complete the dcp node

The DCP block present on MX6SL is compatible with the one on MX28,
so add the compatible string and also complete the interrupt entries.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx6sl.dtsi

@@ -670,8 +670,11 @@ lcdif: lcdif@020f8000 {
 			};
 
 			dcp: dcp@020fc000 {
+				compatible = "fsl,imx6sl-dcp", "fsl,imx28-dcp";
 				reg = <0x020fc000 0x4000>;
-				interrupts = <0 99 IRQ_TYPE_LEVEL_HIGH>;
+				interrupts = <0 99 IRQ_TYPE_LEVEL_HIGH>,
+					     <0 100 IRQ_TYPE_LEVEL_HIGH>,
+					     <0 101 IRQ_TYPE_LEVEL_HIGH>;
 			};
 		};