dpll: netlink/core: change pin frequency set behavior

Align the approach of pin frequency set behavior with the approach
introduced with pin phase adjust set.
Fail the request if any of devices did not registered the callback ops.
If callback op on any pin's registered device fails, return error and
rollback the value to previous one.

Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>