Adapter Shutdown and Unregistration cleanup

- Correct the logic around hba shutdown. Prior to final reset, the
  driver must wait for all XRIs to return from the adapter. Added logic
  to poll, progressively slowing the poll rate as delay gets longer.
- Correct behavior around the rsvd1 field in UNREG_RPI_ALL mailbox
  completion and final rpi cleanup.
- Updated logic to move pending VPI registrations to their completion
  in cases where a CVL may be received while registration in progress.
- Added unreg all rpi mailbox command before unreg vpi.
Signed-off-by: NAlex Iannicelli <alex.iannicelli@emulex.com>
Signed-off-by: NJames Smart <james.smart@emulex.com>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>