Qualcomm Serial Peripheral Interface (SPI)

Required properties:
- compatible : should be "qcom,spi-qup-v2".
- reg : offset and length of the QUP register map.
- interrupts : should contain the QUP core interrupt.
- spi-max-frequency : specifies maximum SPI clock frequency, Units - Hz.

Example:
	spi@f9924000 {
		compatible = "qcom,spi-qup-v2";
		reg = <0xf9924000 0x1000>;
		interrupts = <96>;
		spi-max-frequency = <24000000>;
	};

