net/mlx5: Fix the size of modify QP mailbox

Add 16 reserved bytes at the end of mlx5_modify_qp_mbox_in to
match the hardware spec definition.

Fixes: e126ba97dba9 ('mlx5: Add driver for Mellanox Connect-IB adapters')
Signed-off-by: Majd Dibbiny <majd@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/mlx5/qp.h

@@ -560,6 +560,7 @@ struct mlx5_modify_qp_mbox_in {
 	__be32			optparam;
 	u8			rsvd0[4];
 	struct mlx5_qp_context	ctx;
+	u8			rsvd2[16];
 };
 
 struct mlx5_modify_qp_mbox_out {