ARM: dts: keystone: k2g-evm: Move audio oscillator assigned clock to mcasp

Setting assigned clock with a dependency on itself for k2g_clks
creates a circular dependency. Instead, Lets model the audio clock
as a assigned-clock configuration for mcasp and set it up as the
first clock assigned-clock to be satisfied. Following the standard
convention, we use null entries to indicate entries that doesn't need
to be programmed.

Reviewed-by: Tero Kristo <[e-mail]>
Signed-off-by: Nishanth Menon <[e-mail]>
Signed-off-by: Santosh Shilimkar <[e-mail]>

arch/arm/boot/dts/keystone-k2g-evm.dts

···
 	};
 };
 
-&k2g_clks {
-	/* on the board 22.5792MHz is connected to AUDOSC_IN */
-	assigned-clocks = <&k2g_clks 0x4c 2>;
-	assigned-clock-rates = <22579200>;
-};
-
 &mcasp2 {
 	#sound-dai-cells = <0>;
 
 	pinctrl-names = "default";
 	pinctrl-0 = <&mcasp2_pins>;
 
-	assigned-clocks = <&k2g_clks 0x6 1>;
-	assigned-clock-parents = <&k2g_clks 0x6 2>;
+	assigned-clocks = <&k2g_clks 0x4c 2>, <&k2g_clks 0x6 1>;
+	assigned-clock-parents = <0>, <&k2g_clks 0x6 2>;
+	assigned-clock-rates = <22579200>, <0>;
 
 	status = "okay";