dpll: allocate pin ids in cycle

Pin ID is just a number. Nobody should rely on a certain value, instead,
user should use either pin-id-get op or RTNetlink to get it.

Unify the pin ID allocation behavior with what there is already
implemented for dpll devices.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20231212150605.1141261-1-jiri@resnulli.us


Signed-off-by: Jakub Kicinski <kuba@kernel.org>