ASoC: atmel-i2s: dt-bindings: Remove unnecessary phandle to aclk

- clock-names:    Should be one of each entry matching the clocks phandles list:

                  - "pclk" (peripheral clock) Required.

                  - "gclk" (generated clock) Optional (1).

                  - "aclk" (Audio PLL clock) Optional (1).

                  - "muxclk" (I2S mux clock) Optional (1).

Optional properties:

- princtrl-names: Should contain only one value - "default".

(1) : Only the peripheral clock is required. The generated clock, the Audio

      PLL clock adn the I2S mux clock are optional and should only be set

      together, when Master Mode is required.

(1) : Only the peripheral clock is required. The generated clock and the I2S

      mux clock are optional and should only be set together, when Master Mode

      is required.

Example:

			(AT91_XDMAC_DT_MEM_IF(0) | AT91_XDMAC_DT_PER_IF(1) |

			 AT91_XDMAC_DT_PERID(32))>;

		dma-names = "tx", "rx";

		clocks = <&i2s0_clk>, <&i2s0_gclk>, <&audio_pll_pmc>, <&i2s0muxck>;

		clock-names = "pclk", "gclk", "aclk", "muxclk";

		clocks = <&i2s0_clk>, <&i2s0_gclk>, <&i2s0muxck>;

		clock-names = "pclk", "gclk", "muxclk";

		pinctrl-names = "default";

		pinctrl-0 = <&pinctrl_i2s0_default>;

	};