ice: add ref-sync dpll pins

Implement reference sync input pin get/set callbacks, allow user space
control over dpll pin pairs capable of reference sync support.

Reviewed-by: Milena Olech <milena.olech@intel.com>
Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
Link: https://patch.msgid.link/20250626135219.1769350-4-arkadiusz.kubalewski@intel.com


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