scsi: lpfc: Rework locations of ndlp reference taking

Now that the driver has gone to a normal ref interface (with no odd logic)
the discovery logic needs to be updated to reworked so that it properly
takes references when it should and give them up when it should.

Rework the driver for the following get/put model:

 - Move gets to just before an I/O is issued. Add gets for places where an
   I/O was issued without one.

 - Ensure that failures from lpfc_nlp_get() are handled by the driver.

 - Check and fix the placement of lpfc_nlp_puts relative to io completions.
   Note: some of these paths may not release the reference on the exact io
   completion as the reference is held as the code takes another step in
   the discovery thread and which may cause another io to be issued.

 - Rearrange some code for error processing and calling lpfc_nlp_put.

 - Fix some places of incorrect reference freeing that was causing the
   premature releasing of the structure.

 - Nvmet plogi handling performs unreg_rpi's. The reference counts were
   unbalanced resulting in premature node removal. In some cases this
   caused loss of node discovery. Corrected the reftaking around nvmet
   plogis.

Nodes that experience devloss now get released from the node list now that
there is a proper reference taking.

Link: https://lore.kernel.org/r/20201115192646.12977-3-james.smart@broadcom.com


Co-developed-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>