utils_test.libvirt: Add function to create xml for hostdev device.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
utils_misc: Add VFIO relative functions.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
virttest.libvirt_vm: Add functions to get vm pci devices.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
utils_misc.VFIO: Fix bugs for class and functions.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
virttest.libvirt_xml: Support to set boot order for hostdev.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
Merge pull request #1839 from yumingfei/vfio

VFIO: Add class and functions to operate vfio.