The new format is: domain.bus.device.function
For this format, since we use '.' as separator,
to avoid misusing, we only support the following:
1 domain.bus.device.function ( 4 values provided)
2 bus.device.function (3 values provoided with domain = 0)
3 bus.device (2 values provided with domain = 0, function = 0)
Change-Id: Ide03db38b4ac7802cf36f0e536e8b997101d6cd3
Signed-off-by: Ziye Yang <ziye.yang@intel.com>