mlx4_core: Don't free special QPs in QP number bitmap

Special QPs are not allocated using the regular QP number bitmap, so
when they are destroyed, their QP number should not be freed in the
bitmap.

Found by Dotan Barak of Mellanox.

Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/net/mlx4/qp.c b/drivers/net/mlx4/qp.c
index 19b48c7..278414b 100644
--- a/drivers/net/mlx4/qp.c
+++ b/drivers/net/mlx4/qp.c
@@ -240,7 +240,8 @@
 	mlx4_table_put(dev, &qp_table->auxc_table, qp->qpn);
 	mlx4_table_put(dev, &qp_table->qp_table, qp->qpn);
 
-	mlx4_bitmap_free(&qp_table->bitmap, qp->qpn);
+	if (qp->qpn < dev->caps.sqp_start + 8)
+		mlx4_bitmap_free(&qp_table->bitmap, qp->qpn);
 }
 EXPORT_SYMBOL_GPL(mlx4_qp_free);