node_device: introduce new capability FC_RPORT

node_device: introduce new capability FC_RPORT

Similar to scsi_host and fc_host, there is a relation between a
scsi_target and its transport specific fc_remote_port. Let's expose this
relation and relevant information behind it.

An example for a virsh nodedev-dumpxml:

    virsh # nodedev-dumpxml scsi_target0_0_0
    <device>
      <name>scsi_target0_0_0</name>
      <path>/sys/devices/[...]/host0/rport-0:0-0/target0:0:0</path>
      <parent>scsi_host0</parent>
      <capability type='scsi_target'>
        <target>target0:0:0</target>
        <capability type='fc_remote_port'>
          <rport>rport-0:0-0</rport>
          <wwpn>0x9d73bc45f0e21a86</wwpn>
        </capability>
      </capability>
    </device>

Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Signed-off-by: Bjoern Walk <bwalk@linux.vnet.ibm.com>