Qualcomm SPMI Controller (PMIC Arbiter)

Required properties:
- cell-index : the bus identifier.
- compatible : should be "qcom,spmi-pmic-arb".
- reg : offset and length of the PMIC Arbiter Core register map.
- reg : offset and length of the PMIC Arbiter Interrupt controller register map.
- interrupts : the PMIC Arbiter interrupt.
- qcom,pmic-arb-ee : the execution environment (EE) identifier.
- qcom,pmic-arb-channel : the assigned channel number for channel registers.
- qcom,pmic-arb-ppid-map : an array used to map a 12-bit PPID to 8-bit APID.

Peripherals on the SPMI bus are identified with a 12-bit identifier (PPID)
which is composed of a 4-bit slave address and an 8-bit peripheral identifier.
The PMIC Arbiter hardware uses an 8-bit APID (Arbiter Peripheral Identifier)
internally.  Software needs the mapping between the APID and the PPID.
Up to a maximum of 256 peripherals are supported and the mapping is target
specific.

Data format of pmic-arb-ppid-map:
<0x13100001>
value is 32 bit.
MSB 12 bits are the PPID
12 bits padding
LSB 8 bit are the APID

Example:

	qcom,spmi@fc4c0000 {
		cell-index = <0>;
		compatible = "qcom,spmi-pmic-arb";
		reg = <0xfc4cf000 0x1000>,
		      <0Xfc4cb000 0x1000>;
		interrupts = <0>;
		qcom,pmic-arb-ee = <0>;
		qcom,pmic-arb-channel = <0>;
		qcom,pmic-arb-ppid-map = <0x13000000>, /* PPID 0x130, APID 0 */
					 <0x13100001>, /* PPID 0x131, APID 1 */
	};


