Every GPIO controller node must have #gpio-cells property defined,
this information will be used to translate gpio-specifiers.

On CPM1 devices, all ports are using slightly different register layouts.
Ports A, C and D are 16bit ports and Ports B and E are 32bit ports.

On CPM2 devices, all ports are 32bit ports and use a common register layout.

Required properties:
- compatible : "fsl,cpm1-pario-bank-a", "fsl,cpm1-pario-bank-b",
  "fsl,cpm1-pario-bank-c", "fsl,cpm1-pario-bank-d",
  "fsl,cpm1-pario-bank-e", "fsl,cpm2-pario-bank"
- #gpio-cells : Should be two. The first cell is the pin number and the
  second cell is used to specify optional paramters (currently unused).
- gpio-controller : Marks the port as GPIO controller.

Example of three SOC GPIO banks defined as gpio-controller nodes:

	CPM1_PIO_A: gpio-controller@950 {
		#gpio-cells = <2>;
		compatible = "fsl,cpm1-pario-bank-a";
		reg = <0x950 0x10>;
		gpio-controller;
	};

	CPM1_PIO_B: gpio-controller@ab8 {
		#gpio-cells = <2>;
		compatible = "fsl,cpm1-pario-bank-b";
		reg = <0xab8 0x10>;
		gpio-controller;
	};

	CPM1_PIO_E: gpio-controller@ac8 {
		#gpio-cells = <2>;
		compatible = "fsl,cpm1-pario-bank-e";
		reg = <0xac8 0x18>;
		gpio-controller;
	};

Add documentation for CPM GPIO banks
powerpc: Add documentation for CPM GPIO banks

Signed-off-by: Jochen Friedrich <a43c420013ca055cc92ab03cc74d6f3bd5524c38@scram.de>
Signed-off-by: Kumar Gala <383ef5577c6e1178b93f59ec8d0936f76d2a98c4@kernel.crashing.org>
