* Atmel I2S controller

Required properties:
- compatible:     Should be "atmel,sama5d2-i2s".
- reg:            Should be the physical base address of the controller and the
                  length of memory mapped region.
- interrupts:     Should contain the interrupt for the controller.
- dmas:           Should be a list of pairs of DMA controller phandle and flags.
- dma-names:      Should be a list of DMA channel name among "rx", "tx" or
                  "rx-tx".
- clocks:         Should be a list of phandles of clocks used by the controller
                  (1).
- clock-names:    Should be a list matching the clocks phandles list:
                  - "pclk" (peripheral clock) Required.
                  - "gclk" (generated clock) Optional (1).
                  - "aclk" (Audio PLL clock) Optional (1).

Optional properties:
- pinctrl-0:      Should specify pin control groups used for this controller.
- princtrl-names: Should contain only one value - "default".


(1) : Only the peripheral clock is required. The generated clock and the Audio
      PLL clock are optional and should only be set together.

Example:

	i2s@f8050000 {
		compatible = "atmel,sama5d2-i2s";
		reg = <0xf8050000 0x300>;
		interrupts = <54 IRQ_TYPE_LEVEL_HIGH 7>;
		dmas = <&dma0
			(AT91_XDMAC_DT_MEM_IF(0) | AT91_XDMAC_DT_PER_IF(1) |
			 AT91_XDMAC_DT_PERID(31))>,
		       <&dma0
			(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>;
		clock-names = "pclk", "gclk", "aclk";
		pinctrl-names = "default";
		pinctrl-0 = <&pinctrl_i2s0_default>;
	};
