ice: Mark extack argument as __always_unused

Commit 87b0984e ("net: Add extack argument to ndo_fdb_add()") in
net-next added an extended parameter to the .ndo_fdb_add op and changed
ice_fdb_add() accordingly. Update the function header and add the
__always_unused attribute to the new parameter to avoid -Wunused-parameter
warnings.
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>

drivers/net/ethernet/intel/ice/ice_main.c

@@ -2435,11 +2435,12 @@ static void ice_set_rx_mode(struct net_device *netdev)
  * @addr: the MAC address entry being added
  * @vid: VLAN id
  * @flags: instructions from stack about fdb operation
+ * @extack: netlink extended ack
  */
-static int ice_fdb_add(struct ndmsg *ndm, struct nlattr __always_unused *tb[],
-		       struct net_device *dev, const unsigned char *addr,
-		       u16 vid, u16 flags,
-		       struct netlink_ext_ack *extack)
+static int
+ice_fdb_add(struct ndmsg *ndm, struct nlattr __always_unused *tb[],
+	    struct net_device *dev, const unsigned char *addr, u16 vid,
+	    u16 flags, struct netlink_ext_ack __always_unused *extack)
 {
 	int err;