Feature: allow SDIO slave reset using callback instead of GPIO (EHM-104)

[renzenicolai]

Description

Adds a kconfig option for resetting the SDIO slave using a callback function instead of a GPIO.

This change is needed because on my product the reset line of the ESP32-C6 slave is not directly connected to the ESP32-P4.

This PR adds support for optionally defining a function in user code to replace the reset action normally executed using a GPIO pin, allowing for a custom reset procedure. In our case we send a command to an I2C device in order to reset the ESP32-C6 radio.

Related

Testing

Tested on our hardware using an ESP32-C6 as SDIO slave device.

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Checklist

Before submitting a Pull Request, please ensure the following:

• 🚨 This PR does not introduce breaking changes.
• All CI checks (GH Actions) pass.
• Documentation is updated as needed.
• Tests are updated or added as necessary.
• Code is well-commented, especially in complex areas.
• Git history is clean — commits are squashed to the minimum necessary.