pinctrl: DT: extend the pinmux property to support integers array

maintain.

For cases like this, the pin controller driver may use the pinmux helper

property, where the pin identifier is packed with mux configuration settings

in a single integer.

property, where the pin identifier is provided with mux configuration settings

in a pinmux group. A pinmux group consists of the pin identifier and mux

settings represented as a single integer or an array of integers.

The pinmux property accepts an array of integers, each of them describing

The pinmux property accepts an array of pinmux groups, each of them describing

a single pin multiplexing configuration.

pincontroller {

	state_0_node_a {

		pinmux = <PIN_ID_AND_MUX>, <PIN_ID_AND_MUX>, ...;

		pinmux = <PINMUX_GROUP>, <PINMUX_GROUP>, ...;

	};

};

Each individual pin controller driver bindings documentation shall specify

how those values (pin IDs and pin multiplexing configuration) are defined and

assembled together.

how pin IDs and pin multiplexing configuration are defined and assembled

together in a pinmux group.

== Generic pin configuration node content ==

- pinmux takes a list of pin IDs and mux settings as required argument. The

  specific bindings for the hardware defines:

  - How pin IDs and mux settings are defined and assembled together in a single

    integer.

    integer or an array of integers.

- bias-pull-up, -down and -pin-default take as optional argument on hardware

  supporting it the pull strength in Ohm. bias-disable will disable the pull.