add sriov, power state and numa node info in PciDevice

[jj-asama]

I found these important for the observability tool I am building. Once this is merged, I will be adding these to the p8s collector as well.
Test case added from a Intel E810 NIC.

	NumaNode        *int32 // /sys/bus/pci/devices/<Location>/numa_node

	SriovDriversAutoprobe *bool   // /sys/bus/pci/devices/<Location>/sriov_drivers_autoprobe
	SriovNumvfs           *uint32 // /sys/bus/pci/devices/<Location>/sriov_numvfs
	SriovOffset           *uint32 // /sys/bus/pci/devices/<Location>/sriov_offset
	SriovStride           *uint32 // /sys/bus/pci/devices/<Location>/sriov_stride
	SriovTotalvfs         *uint32 // /sys/bus/pci/devices/<Location>/sriov_totalvfs
	SriovVfDevice         *uint32 // /sys/bus/pci/devices/<Location>/sriov_vf_device
	SriovVfTotalMsix      *uint64 // /sys/bus/pci/devices/<Location>/sriov_vf_total_msix

	D3coldAllowed *bool          // /sys/bus/pci/devices/<Location>/d3cold_allowed
	PowerState    *PciPowerState // /sys/bus/pci/devices/<Location>/power_state

I am not really interested in Offset, Stride VfDevice and MSI-X. Just added for completeness. Please let me know if I should rather remove them.

@discordianfish for your kind review.

ref: https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-bus-pci

[SuperQ]

Are we sure numa_node is always going to exist? Even on older kernels? We tend to support some pretty old kernel versions here.

[jj-asama]

From 2.6.21 onwards as per
https://kernelnewbies.org/Linux_2_6_21
and
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=81bb0e198b4638ac65233b316f4588639dfe1fcd

But I think I made a mixup here. I used *int32 to make it optional. But added to this list of mandatory files. Will move it out.

[SuperQ]

Thanks for double checking the versions. We used to support 2.6.32, but recently Go changed to >= 3.2.0.

So that works.

[SuperQ]

Thanks, this mostly looks good. Question about the new required file.

[jj-asama]

Thanks, this mostly looks good. Question about the new required file.
@SuperQ I have moved it to the other set of optional files.

[SuperQ]

Thanks!