In a large SAN testing configuration, frequent target port toggle tests are
occasionally resulting in missing lun path rediscoveries.  An outstanding
PRLI can be inflight when a target RSCN dissappearance occurs, causing the
driver to retry PRLIs using invalid rpi contexts.

Fix by verifying that an ndlp's state was not restarted from PRLI_ISSUE
due to an intermediate RSCN.  If not in a valid state, early exit PRLI
completion handling.

The last follow up RSCN indicating target reappearance retriggers
PLOGI/PRLI with a valid rpi context and is expected to succeed in LUN path
rediscovery.
Signed-off-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>