Add support for multi path devices.

... to get 'hostX:Y' from:
    /sys/devices/pci0000:00/0000:00:0b.0/0000:03:00.0/host0/port-0:0/end_device-0:0/target0:0:0/0:0:0:0
    /sys/devices/pci0000:00/0000:00:15.0/0000:03:00.0/host2/port-2:0/expander-2:0/port-2:0:0/end_device-2:0:0/target2:0:0/2:0:0:0
Closes: #3