[SCSI] zfcp: Replace FC4 constants with information from exchange port

The FC4 types are already available from exchange port.  Use this for
reporting the FC4 types, instead of having the value hardcoded in
zfcp.

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