sx126x: add libgpiod v2 support via version-agnostic GPIO HAL

[exepirit]

Migrates sx126x driver to libgpiod v2 API while maintaining backward compatibility with v1 through an abstraction layer.

Resolves #2

[strijar]

Why did you rename and change the port type? It will always be /dev/gpiochipN, so knowing the N from config file, you can easily generate the required text string. In your case, it's easier to make a mistake in a text parameter than in a single numerical parameter.

[exepirit]

Since libgpiod v2 moved from chip index to device path. I think that in long term, using device path will eliminate the need to convert N to path (if libgpiod v1 eventually deprecated in RNode).

In your case, it's easier to make a mistake in a text parameter than in a single numerical parameter.

Descriptive error messages can help the user to find a mistakes.

There is no problem to use chip index or support both variants. What do you think about this?

[strijar]

There is no problem to use chip index or support both variants. What do you think about this?

Yes, I think using an index is more logical. Will you do it this way?

[exepirit]

No problem. I made the changes to use chip/port index. Now in config.h and sx1262.c files are unchanged compare to upstream.

[strijar]

Thanks! I'll check it out in a few days and merge the changes.