[SCSI] bfa: Fabric Assigned Address implementation fix

- Made changes such that once the PWWN is acquired from the fabric through FAA,
  and if the FAPWWN configuration is modified on the switch side, driver should
  show relevant information to the user.
- Added logic to cache the reason code when the given port is disabled implicitl
  due to FAA error condition.
- If the port is disabled, while sending SCN to upper layer, update the
  reason code appropriately. With this, BFA FC port state machine will enter
  into faa_err_config state. This state will be shown to the user.

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