Switch from Xenctrl.hvm_check_pvdriver to Xenctrl.hvm_param_get

The former is technical debt in the hypervisor patchqueue, while the latter is
an upstream binding.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

ocaml/xenopsd/xc/domain.ml

@@ -600,7 +600,7 @@ let shutdown_wait_for_ack (t : Xenops_task.task_handle) ~timeout ~xc ~xs domid
  | true, `pvh ->
  true (* PVH guests are also always enlightened *)
  | true, `hvm ->
- Xenctrl.hvm_check_pvdriver xc domid (* checks for HVM_CALLBACK_IRQ *)
+ (Xenctrl.hvm_param_get xc domid HVM_PARAM_CALLBACK_IRQ) <> 0L
  | true, `pv ->
  failwith "Internal error, should never happen"
  in