* SPI driver for Cadence QSPI Controller

Required properties:
- compatible : Should be "cadence,qspi".
- reg : Contains two entries, each of which is a tuple consisting of a
	physical address and length.  The first entry is the address and
	length of the controller register set.  The second entry is the
	address and length of the QSPI Controller data area.
- interrupts : Unit interrupt specifier for the controller interrupt.
- ext-decoder : Value of 0 means no external chipselect decoder is
	connected, 1 means there is an external chipselect decoder connected.
- num-chipselect : Number of chip select lines.
- fifo-depth : Size of the data FIFO in bytes.
- bus-num : Number of the SPI bus to which the controller is connected.

Optional properties:
No optional properties

Example:

	qspi: spi@ff705000 {
		compatible = "cadence,qspi";
		#address-cells = <1>;
		#size-cells = <0>;
		reg = <0xff705000 0x1000>,
			<0xffa00000 0x1000>;
		interrupts = <0 151 4>;
		clocks = <&qspi_clk>;
		ext-decoder = <0>;
		num-chipselect = <4>;
		fifo-depth = <128>;
		bus-num = <2>;
	}
