The hypervisor expects the timeout from the hypercall to be in
nanoseconds, so document this correctly. Also correctly document
what happens when timeout is set to zero.
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>