net/mlx4_core: Fix device capabilities dumping

We are dumping device capabilities which are supported both by the
firmware and the driver. Align the array that holds the capability
strings with this practice.

Reported-by: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>