[SCSI] zfcp: Enable auto-port discovery for NPIV.

Since we're setting the host port type now to FC_PORTTYPE_NPIV
for adapters running in NPIV mode we should allow this port type
for auto-port scanning as well.

Signed-off-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>