x86,hvm: enable VCPUOP_register_vcpu_info op in hvm hypercall

pvhvm running with more than 32 vcpus and pv_irq/pv_time enabled
need vcpu placement to work, or else it will softlockup.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Committed-by: Keir Fraser <keir@xen.org>

xen/arch/x86/hvm/hvm.c

@@ -2794,6 +2794,7 @@ static long hvm_vcpu_op(
     case VCPUOP_stop_periodic_timer:
     case VCPUOP_set_singleshot_timer:
     case VCPUOP_stop_singleshot_timer:
+    case VCPUOP_register_vcpu_info:
         rc = do_vcpu_op(cmd, vcpuid, arg);
         break;
     default:
@@ -2869,6 +2870,7 @@ static long hvm_vcpu_op_compat32(
     case VCPUOP_stop_periodic_timer:
     case VCPUOP_set_singleshot_timer:
     case VCPUOP_stop_singleshot_timer:
+    case VCPUOP_register_vcpu_info:
         rc = compat_vcpu_op(cmd, vcpuid, arg);
         break;
     default: