* Atmel PDMIC driver under ALSA SoC architecture

Required properties:
- compatible
	Should be "atmel,sama5d2-pdmic".
- reg
	Should contain PDMIC registers location and length.
- interrupts
	Should contain the IRQ line for the PDMIC.
- dmas
	One DMA specifiers as described in atmel-dma.txt and dma.txt files.
- dma-names
	Must be "rx".
- clock-names
	Required elements:
	- "pclk"	peripheral clock
	- "gclk"	generated clock
- clocks
	Must contain an entry for each required entry in clock-names.
	Please refer to clock-bindings.txt.
- atmel,mic-min-freq
	The minimal frequency that the micphone supports.
- atmel,mic-max-freq
	The maximal frequency that the micphone supports.

Optional properties:
- pinctrl-names, pinctrl-0
	Please refer to pinctrl-bindings.txt.
- atmel,model
	The user-visible name of this sound card.
	The default value is "PDMIC".
- atmel,mic-offset
	The offset that should be added.
	The range is from -32768 to 32767.
	The default value is 0.

Example:
	pdmic@f8018000 {
				compatible = "atmel,sama5d2-pdmic";
				reg = <0xf8018000 0x124>;
				interrupts = <48 IRQ_TYPE_LEVEL_HIGH 7>;
				dmas = <&dma0
					(AT91_XDMAC_DT_MEM_IF(0) | AT91_XDMAC_DT_PER_IF(1)
					| AT91_XDMAC_DT_PERID(50))>;
				dma-names = "rx";
				clocks = <&pdmic_clk>, <&pdmic_gclk>;
				clock-names = "pclk", "gclk";

				pinctrl-names = "default";
				pinctrl-0 = <&pinctrl_pdmic_default>;
				atmel,model = "PDMIC @ sama5d2_xplained";
				atmel,mic-min-freq = <1000000>;
				atmel,mic-max-freq = <3246000>;
				atmel,mic-offset = <0x0>;
	};