hw/isa/isa-bus: Set category of the "isabus-bridge" device

It has "bridge" in its name, so it should be in the category
DEVICE_CATEGORY_BRIDGE.
Signed-off-by: NThomas Huth <thuth@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

hw/isa/isa-bus.c

@@ -219,6 +219,7 @@ static void isabus_bridge_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
 
+    set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
     dc->fw_name = "isa";
 }