Cirrus Logic CLPS711X Interrupt Controller

Required properties:

- compatible: Should be "cirrus,ep7209-intc".
- reg: Specifies base physical address of the registers set.
- interrupt-controller: Identifies the node as an interrupt controller.
- #interrupt-cells: Specifies the number of cells needed to encode an
  interrupt source. The value shall be 1.

The interrupt sources are as follows:
ID	Name	Description
---------------------------
1:	BLINT	Battery low (FIQ)
3:	MCINT	Media changed (FIQ)
4:	CSINT	CODEC sound
5:	EINT1	External 1
6:	EINT2	External 2
7:	EINT3	External 3
8:	TC1OI	TC1 under flow
9:	TC2OI	TC2 under flow
10:	RTCMI	RTC compare match
11:	TINT	64Hz tick
12:	UTXINT1	UART1 transmit FIFO half empty
13:	URXINT1	UART1 receive FIFO half full
14:	UMSINT	UART1 modem status changed
15:	SSEOTI	SSI1 end of transfer
16:	KBDINT	Keyboard
17:	SS2RX	SSI2 receive FIFO half or greater full
18:	SS2TX	SSI2 transmit FIFO less than half empty
28:	UTXINT2	UART2 transmit FIFO half empty
29:	URXINT2	UART2 receive FIFO half full
32:	DAIINT	DAI interface (FIQ)

Example:
	intc: interrupt-controller {
		compatible = "cirrus,ep7312-intc", "cirrus,ep7209-intc";
		reg = <0x80000000 0x4000>;
		interrupt-controller;
		#interrupt-cells = <1>;
	};
