Texas Instruments McASP controller

Required properties:
- compatible :
	"ti,dm646x-mcasp-audio"	: for DM646x platforms
	"ti,da830-mcasp-audio"	: for both DA830 & DA850 platforms
	"ti,omap2-mcasp-audio"	: for OMAP2 platforms (TI81xx, AM33xx)

- reg : Should contain McASP registers offset and length
- interrupts : Interrupt number for McASP
- op-mode : I2S/DIT ops mode.
- tdm-slots : Slots for TDM operation.
- num-serializer : Serializers used by McASP.
- serial-dir : A list of serializer pin mode. The list number should be equal
		to "num-serializer" parameter. Each entry is a number indication
		serializer pin direction. (0 - INACTIVE, 1 - TX, 2 - RX)


Optional properties:

- ti,hwmods : Must be "mcasp<n>", n is controller instance starting 0
- tx-num-evt : FIFO levels.
- rx-num-evt : FIFO levels.
- sram-size-playback : size of sram to be allocated during playback
- sram-size-capture  : size of sram to be allocated during capture

Example:

mcasp0: mcasp0@1d00000 {
	compatible = "ti,da830-mcasp-audio";
	#address-cells = <1>;
	#size-cells = <0>;
	reg = <0x100000 0x3000>;
	interrupts = <82 83>;
	op-mode = <0>;		/* MCASP_IIS_MODE */
	tdm-slots = <2>;
	num-serializer = <16>;
	serial-dir = <
			0 0 0 0	/* 0: INACTIVE, 1: TX, 2: RX */
			0 0 0 0
			0 0 0 1
			2 0 0 0 >;
	tx-num-evt = <1>;
	rx-num-evt = <1>;
};