ice: Fix unused variable build warning

Commit 2fd527b7 ("net: ndo_bridge_setlink: Add extack") added a new
parameter "extack" to ice_bridge_setlink but this parameter isn't used
by the function. This results in a warning: unused parameter ‘extack’
[-Wunused-parameter]. Fix that by adding an "__always_unused" qualifier.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>