drivers pps/generators: add dummy PPS generator

This dummy PPS generator can be used for debugging and documentation
purposes.

Signed-off-by: Rodolfo Giometti <giometti@enneenne.com>
Link: https://lore.kernel.org/r/20241108073115.759039-3-giometti@enneenne.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>