Drivers: hv: vmbus: add numa_node to sysfs

Being able to find the numa_node for a device is useful for userspace
drivers (DPDK) and also for diagnosing performance issues.  This makes
vmbus similar to pci.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/ABI/stable/sysfs-bus-vmbus

@@ -42,6 +42,13 @@ Contact:	K. Y. Srinivasan <kys@microsoft.com>
 Description:	The 16 bit vendor ID of the device
 Users:		tools/hv/lsvmbus and user level RDMA libraries
 
+What:		/sys/bus/vmbus/devices/<UUID>/numa_node
+Date:		Jul 2018
+KernelVersion:	4.19
+Contact:	Stephen Hemminger <sthemmin@microsoft.com>
+Description:	This NUMA node to which the VMBUS device is
+		attached, or -1 if the node is unknown.
+
 What:		/sys/bus/vmbus/devices/<UUID>/channels/<N>
 Date:		September. 2017
 KernelVersion:	4.14