ice: add CGU info to devlink info callback

If Clock Generation Unit is present on NIC board user shall know its
details.
Provide the devlink info callback with a new:
- fixed type object (cgu.id) indicating hardware variant of onboard CGU,
- running type object (fw.cgu) consisting of CGU id, config and firmware
versions.
These information shall be known for debugging purposes.

Test (on NIC board with CGU)
$ devlink dev info <bus_name>/<dev_name> | grep cgu
        cgu.id 36
        fw.cgu 8032.16973825.6021

Test (on NIC board without CGU)
$ devlink dev info <bus_name>/<dev_name> | grep cgu -c
0

Reviewed-by: Larysa Zaremba <larysa.zaremba@intel.com>
Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>