drivers: pinctrl: Use common pinctrl DTS bindings for Cypress psoc6

[henrikbrixandersen]

Is your enhancement proposal related to a problem? Please describe.
As noted in #39740 the Cypress PSoC6 implementation uses a custom devicetree pinctrl representation (as seen in dts/arm/cypress/psoc6-pinctrl.dtsi).

Describe the solution you'd like
The Cypress PSoC6 implementation should use one of the standard Zephyr pinctrl devicetree representations as described in https://docs.zephyrproject.org/latest/hardware/pinctrl/index.html#devicetree-representation along with a pinctrl driver.

Describe alternatives you've considered
None.

Additional context
None.

[gmarull]

@npal-cy This has been open for a while, is the platform maintained? Should it be removed or is it going to be fixed?

[ifyall]

@gmarull, these platforms are being maintained. We will generate a plan internally to bring them up to standards.

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