Placeholder for V4V hypercall and VIRQ numbers

Placeholder for V4V hypercall and VIRQ numbers

The V4V Xen functionality is currently in our product trees for
XenClient b= ut is not yet in a state suitable for submission. We hope
to make available= the rest of the V4V functionality in the not too
distant future. Since the= se values are already in use in our
product, we would like to reserve them = in open source to prevent
issues or incompatibilities down the road.

Signed-off-by: Ross Philipson <ross.philipson@citrix.com>