drivers: gpio: smartbond: Fix PDC GPIO port selection

[ioannis-karachalios]

Describe the bug

When registering a PDC entry so that a I/O pin can act as wakeup/triggering source, the GPIO port selection is based on the device driver instance numbering. That is not correct as described by Zephyr documentation which declares that "instance numbers in no way reflect any numbering scheme". Therefore, if a wrong port is registered, the device will never exit the sleep state (application core should be turned off at that time). What is more, each port exposes different number of I/O pins. #91517 is the PR that solves that issue by introducing a DTS property so that each GPIO block instance explicitly defines its indexing.

Regression

• This is a regression.

Steps to reproduce

No response

Relevant log output

Impact

Functional Limitation – Some features not working as expected, but system usable.

Environment

No response

Additional Context

No response