mlx4: FIX error flow when initializing EQ table

If mlx4_create_eq() would fail for one of EQ's assigned for
completion handling, the code would try to free the same EQ
we failed to create.
The crash was found by Christoph Lameter

Signed-off-by: Yevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>