ice: Refactor DCB related variables out of the ice_port_info struct

Refactor the DCB related variables out of the ice_port_info_struct. The
goal is to make the ice_port_info struct cleaner.

Signed-off-by: Chinh T Cao <chinh.t.cao@intel.com>
Co-developed-by: Dave Ertman <david.m.ertman@intel.com>
Signed-off-by: Dave Ertman <david.m.ertman@intel.com>
Tested-by: Tony Brelinski <tonyx.brelinski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>