i40e: Fix receive buffer starvation for AF_XDP

Magnus's fix to resolve a potential receive buffer starvation for AF_XDP
got applied to both the i40e_xsk_umem_enable/disable() functions, when it
should have only been applied to the "enable".  So clean up the undesired
code in the disable function.

CC: Magnus Karlsson <magnus.karlsson@intel.com>
Fixes: 1f459bdc ("i40e: fix potential RX buffer starvation for AF_XDP")
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>

drivers/net/ethernet/intel/i40e/i40e_xsk.c

@@ -157,11 +157,6 @@ static int i40e_xsk_umem_disable(struct i40e_vsi *vsi, u16 qid)
 		err = i40e_queue_pair_enable(vsi, qid);
 		if (err)
 			return err;
-
-		/* Kick start the NAPI context so that receiving will start */
-		err = i40e_xsk_wakeup(vsi->netdev, qid, XDP_WAKEUP_RX);
-		if (err)
-			return err;
 	}
 
 	return 0;