scsi: lpfc: Introduce FC_RSCN_MEMENTO flag for tracking post RSCN completion

During an NVMe target reboot, the target may initialize itself as FCP only
during the first RSCN and shortly after trigger a second RSCN claiming NVMe
support.  The timing of these RSCNs occur before FCP-PRLI for the first
RSCN completes leading discovery issues over NVMe.

Change RSCN and NVME-PRLI send logic based on a new FC_RSCN_MEMENTO flag
that signals when lpfc_end_rscn() is completed and serves as a memento that
discovery was started from RSCN.

Link: https://lore.kernel.org/r/20220412222008.126521-20-jsmart2021@gmail.com
Co-developed-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>