ARM: dts: dra7: Add missing hdmi audio DMA channel information

The audio DMA request for hdmi is crossbar 76 and we use sDMA
to handle the data transfer.
Signed-off-by: NPeter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: NTony Lindgren <tony@atomide.com>

arch/arm/boot/dts/dra7.dtsi

@@ -1908,6 +1908,8 @@
 				ti,hwmods = "dss_hdmi";
 				clocks = <&dss_48mhz_clk>, <&dss_hdmi_clk>;
 				clock-names = "fck", "sys_clk";
+				dmas = <&sdma_xbar 76>;
+				dma-names = "audio_tx";
 			};
 		};