probably (I have no fc or iscsi initiators on esxi on our environment) poking around config.storageDevice.hostBusAdapter?
my $hosts_view;
$hosts_view = Vim::find_entity_views(
view_type => 'HostSystem',
properties => [ 'name','config.storageDevice.hostBusAdapter', ],
);
print Dumper $hosts_view;
Edit: I added a iscsi initiator just for testing and it is indeed in there:
'iScsiName' => 'iqn.1998-01.com.vmware:hostname-590171e5',
As i do not have any fibre channel, I have no means of getting this info for that, but it should be quite similar.