ARM: DTS: am57xx-beagle-x15: Select SYS_CLK2 for audio clocks

The tlv320aic3104 codec's master clock is coming from the SoC's CLKOUT2.
Select the SYS_CLK2 (via divider) as parent clock for CLKOUT2 and select
the same clock (SYS_CLK2) for McASP3 AHCLKX clock as well.
SYS_CLK2 is sourced from an external oscillator running 22.5792MHz and it
is coming in to the SoC via the X1_OSC1.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/am57xx-beagle-x15.dts

@@ -173,6 +173,8 @@
 
 		sound0_master: simple-audio-card,codec {
 			sound-dai = <&tlv320aic3104>;
+			assigned-clocks = <&clkoutmux2_clk_mux>;
+			assigned-clock-parents = <&sys_clk2_dclk_div>;
 			clocks = <&clkout2_clk>;
 		};
 	};
@@ -796,6 +798,8 @@
 	pinctrl-names = "default", "sleep";
 	pinctrl-0 = <&mcasp3_pins_default>;
 	pinctrl-1 = <&mcasp3_pins_sleep>;
+	assigned-clocks = <&mcasp3_ahclkx_mux>;
+	assigned-clock-parents = <&sys_clkin2>;
 	status = "okay";
 
 	op-mode = <0>;	/* MCASP_IIS_MODE */