net/mlx4_core: Remove duplicate code line from procedure mlx4_bf_alloc

mlx4_bf_alloc had an unnecessary/duplicate code line. Did no harm,
but not good practice.

Reported by the Mellanox Beijing team.
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/pd.c

@@ -214,7 +214,6 @@ int mlx4_bf_alloc(struct mlx4_dev *dev, struct mlx4_bf *bf, int node)
 		list_add(&uar->bf_list, &priv->bf_list);
 	}
 
-	bf->uar = uar;
 	idx = ffz(uar->free_bf_bmap);
 	uar->free_bf_bmap |= 1 << idx;
 	bf->uar = uar;