mlx4_core: Fix state check in mlx4_qp_modify()

When checking the states passed in, mlx4_qp_modify() accidentally checks
cur_state twice rather than checking cur_state and new_state.  Fix this
to make sure that both values are in-bounds.

Since these values may be passed in from userspace, this bug results in
userspace being able to trigger an oops.
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Cc: stable <stable@kernel.org>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/net/mlx4/qp.c

@@ -113,7 +113,7 @@ int mlx4_qp_modify(struct mlx4_dev *dev, struct mlx4_mtt *mtt,
 	struct mlx4_cmd_mailbox *mailbox;
 	int ret = 0;
 
-	if (cur_state >= MLX4_QP_NUM_STATE || cur_state >= MLX4_QP_NUM_STATE ||
+	if (cur_state >= MLX4_QP_NUM_STATE || new_state >= MLX4_QP_NUM_STATE ||
 	    !op[cur_state][new_state])
 		return -EINVAL;