dpll: add Embedded SYNC feature for a pin

dpll: add Embedded SYNC feature for a pin

Implement and document new pin attributes for providing Embedded SYNC
capabilities to the DPLL subsystem users through a netlink pin-get
do/dump messages. Allow the user to set Embedded SYNC frequency with
pin-set do netlink message.

Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://patch.msgid.link/20240822222513.255179-2-arkadiusz.kubalewski@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>