It's not supported on all ports, adds complexity to the build to generate
pins_af.py, and can mostly be replicated just by printing the pin objects.
Remove support for generating pins_af.py from all ports (nrf, stm32,
renesas-ra, mimxrt, rp2).
This work was funded through GitHub Sponsors.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>