q35: skip q35-acpi-dsdt.aml load if not needed

Only old machine types which don't use the acpi builder (qemu 1.7 + older)
have to load that file for proper acpi support.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

hw/i386/pc_q35.c

@@ -117,7 +117,10 @@ static void pc_q35_init(MachineState *machine)
     }
 
     pc_cpus_init(pcms);
-    pc_acpi_init("q35-acpi-dsdt.aml");
+    if (!pcmc->has_acpi_build) {
+        /* only machine types 1.7 & older need this */
+        pc_acpi_init("q35-acpi-dsdt.aml");
+    }
 
     kvmclock_create();