net/mlx4_en: Initialize RFS filters lock and list in init_netdev

filters_lock might have been used while it was re-initialized.
Moved filters_lock and filters_list initialization to init_netdev instead of
alloc_resources which is called every time the device is configured.

Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>