fix info qtree indention

Without the patch bus properties are are not in line with the other
properties:

[ ... ]
  dev: fw_cfg, id ""
    ctl_iobase = 0x510
    data_iobase = 0x511
      irq 0
      mmio ffffffffffffffff/0000000000000002
      mmio ffffffffffffffff/0000000000000001
[ ... ]

With the patch applied everything is lined up properly:

[ ... ]
  dev: fw_cfg, id ""
    ctl_iobase = 0x510
    data_iobase = 0x511
    irq 0
    mmio ffffffffffffffff/0000000000000002
    mmio ffffffffffffffff/0000000000000001
[ ... ]

Needed to make the autotest qtree parser happy.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>