bna: Introduce ENET as New Driver and FW Interface

Change details:
 - This patch contains the messages, opcodes and structure format for the
   messages and responses exchanged between driver and the FW. In addition
   this patch contains the state machine implementation for Ethport, Enet,
   IOCEth.
 - Ethport object is responsible for receiving link state events, sending
   port enable/disable commands to FW.
 - Enet object is responsible for synchronizing initialization/teardown of
   tx & rx datapath configuration.
 - IOCEth object is responsible for init/un-init of IO Controller in the
   adapter which runs the FW.
 - This patch also contains code for initialization and resource assignment
   for Ethport, Enet, IOCEth, Tx, Rx objects.

Signed-off-by: Rasesh Mody <rmody@brocade.com>
Signed-off-by: David S. Miller <davem@davemloft.net>