tools: hv: add a python script lsvmbus to list VMBus devices

By default lsvmbus lists all the devices in the VMBus.
With -v or -vv, more information is printed, including the VMBus
Rel_ID, class ID, device ID and which channel is bound to which
virtual processor, etc.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>