net/mlx4_en: Datapath resources allocated dynamically

Currently all TX/RX rings and completion queues are part of the
netdev priv structure and are allocated statically. This patch
will change the priv to hold only arrays of pointers and therefore
all TX/RX rings and completetion queues will be allocated
dynamically. This is in preparation for NUMA aware allocations.

Signed-off-by: Yevgeny Petrilin <yevgenyp@mellanox.com>
Signed-off-by: Eugenia Emantayev <eugenia@mellanox.com>
Reviewed-by: Hadar Hen Zion <hadarh@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>