ice: renegotiate link after FW DCB on

When switching from SW DCB to FW DCB it is necessary
to renegotiate DCBx so that the FW agent can have up
to date information about the DCB settings of the link
partner.

Perform an autoneg restart on the link when activating
FW DCB.

Signed-off-by: Dave Ertman <david.m.ertman@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>