isa: QOM'ify ISADevice

Rename its parent field and use DEVICE() where necessary.

Signed-off-by: Andreas Färber <afaerber@suse.de>
diff --git a/hw/isa/isa-bus.c b/hw/isa/isa-bus.c
index 7aa9b89..136d17e 100644
--- a/hw/isa/isa-bus.c
+++ b/hw/isa/isa-bus.c
@@ -156,7 +156,7 @@
     ISADevice *dev;
 
     dev = isa_create(bus, name);
-    qdev_init_nofail(&dev->qdev);
+    qdev_init_nofail(DEVICE(dev));
     return dev;
 }
 
@@ -240,7 +240,7 @@
 
 static char *isabus_get_fw_dev_path(DeviceState *dev)
 {
-    ISADevice *d = (ISADevice*)dev;
+    ISADevice *d = ISA_DEVICE(dev);
     char path[40];
     int off;