Fix implicit logo and RSCN handling for NVMET

NVMET didn't have any RSCN handling at all and
would not execute implicit LOGO when receiving a PLOGI
from an rport that NVMET had in state UNMAPPED.

Clean up the logic in lpfc_nlp_state_cleanup for
initiators (FCP and NVME). NVMET should not respond to
RSCN including allocating new ndlps so this code was
conditionalized when nvmet_support is true.  The check
for NLP_RCV_PLOGI in lpfc_setup_disc_node was moved
below the check for nvmet_support to allow the NVMET
to recover initiator nodes correctly.  The implicit
logo was introduced with lpfc_rcv_plogi when NVMET gets
a PLOGI on an ndlp in UNMAPPED state.  The RSCN handling
was modified to not respond to an RSCN in NVMET.  Instead
NVMET sends a GID_FT and determines if an NVMEP_INITIATOR
it has is UNMAPPED but no longer in the zone membership.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>