[SCSI] lpfc 8.3.12: Fix discovery issues

- Add code to prevent unreg_vpi mailbox command from failing.
- Add code to reset the HBA if unreg_vpi mailbox fails with busy status.
- Remove code that was clearing the nlp_type stored during rport discovery.

Signed-off-by: Alex Iannicelli <alex.iannicelli@emulex.com>
Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>