[SCSI] bfa: Add support for FC Arbitrated Loop topology.

[SCSI] bfa: Add support for FC Arbitrated Loop topology.

- Add private loop topology support at 2G/4G/8G speeds with following
  limitations
  1. No support for multiple initiators in the loop
  2. No public loop support. If attached to a loop with an FL_Port,
     device continues to work as a private NL_Port in the loop
  3. No auto topology detection. User has to manually set the
     configured topology to loop if attaching to loop.
- When loop topology is configured, enabling FC port features
  QoS/Trunk/TRL are not allowed and vice versa.

Signed-off-by: Vijaya Mohan Guvva <vmohan@brocade.com>
Signed-off-by: Krishna Gudipati <kgudipat@brocade.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>