ASoC: atmel-classd: remove aclk clock from DT binding

Since gclk (generated-clk) is now able to determine the rate of the
audio_pll, there is no need for classd to have a direct phandle to the
audio_pll while already having a phandle to gclk.

This binding is used by no board in mainline so it is safe to be
modified.

Signed-off-by: Quentin Schulz <[e-mail]>
Acked-by: Mark Brown <[e-mail]>
Acked-by: Rob Herring <[e-mail]>
Acked-by: Nicolas Ferre <[e-mail]>
Signed-off-by: Stephen Boyd <[e-mail]>

Documentation/devicetree/bindings/sound/atmel-classd.txt

···
 	Must be "tx".
 - clock-names
 	Tuple listing input clock names.
-	Required elements: "pclk", "gclk" and "aclk".
+	Required elements: "pclk" and "gclk".
 - clocks
 	Please refer to clock-bindings.txt.
 - assigned-clocks
 	Should be <&classd_gclk>.
-- assigned-clock-parents
-	Should be <&audio_pll_pmc>.
 
 Optional properties:
 - pinctrl-names, pinctrl-0
···
 			(AT91_XDMAC_DT_MEM_IF(0) | AT91_XDMAC_DT_PER_IF(1)
 			| AT91_XDMAC_DT_PERID(47))>;
 		dma-names = "tx";
-		clocks = <&classd_clk>, <&classd_gclk>, <&audio_pll_pmc>;
-		clock-names = "pclk", "gclk", "aclk";
+		clocks = <&classd_clk>, <&classd_gclk>;
+		clock-names = "pclk", "gclk";
 		assigned-clocks = <&classd_gclk>;
-		assigned-clock-parents = <&audio_pll_pmc>;
 
 		pinctrl-names = "default";
 		pinctrl-0 = <&pinctrl_classd_default>;