PCI: Add domain number check to find_smbios_instance_string()

The function find_smbios_instance_string() does not consider the
PCI domain number.  As a result, SMBIOS type 41 device type instance
would be exported to sysfs for all the PCI domains which have a
PCI device with same bus/device/function, though PCI bus/device/func
from a specific PCI domain has SMBIOS type 41 device type instance
defined.

Address the issue by making find_smbios_instance_string() check PCI domain
number as well.

Reported-by: Shai Fultheim <Shai@ScaleMP.com>
Suggested-by: Shai Fultheim <Shai@ScaleMP.com>
Tested-by: Shai Fultheim <Shai@ScaleMP.com>
Signed-off-by: Sujith Pandel <sujithpshankar@gmail.com>
Signed-off-by: Narendra K <Narendra_K@Dell.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>