net/mlx5: Fix the size of modify QP mailbox

BugLink: https://bugs.launchpad.net/bugs/1878232

commit 418f8399 upstream.

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

Fixes: e126ba97 ('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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ian May <ian.may@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

include/linux/mlx5/qp.h

@@ -539,6 +539,7 @@ struct mlx5_modify_qp_mbox_in {
 	__be32			optparam;
 	u8			rsvd1[4];
 	struct mlx5_qp_context	ctx;
+	u8			rsvd2[16];
 };
 
 struct mlx5_modify_qp_mbox_out {