fsl/fman: fix eth hash table allocation

Fix memory allocation for ethernet address hash table.
The code was wrongly allocating an array for eth hash table which
is incorrect because this is the main structure for eth hash table
(struct eth_hash_t) that contains inside a number of elements.

Fixes: 57ba4c9b

 ("fsl/fman: Add FMan MAC support")
Signed-off-by: Florinel Iordache <florinel.iordache@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>