mainboard/ibase/mb899: transition away from device_t

Replace the use of the old device_t definition inside
mainboard/ibase/mb899.

Change-Id: Id5b460090db58e91b2c210d8633a69114a9c7f6b
Signed-off-by: Antonello Dettori <dev@dettori.io>
Reviewed-on: https://review.coreboot.org/17294
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

src/mainboard/ibase/mb899/romstage.c

@@ -74,7 +74,7 @@ static void ich7_enable_lpc(void)
  */
 static void early_superio_config_w83627ehg(void)
 {
-	device_t dev;
+	pnp_devfn_t dev;
 
 	dev = DUMMY_DEV;
 	pnp_enter_ext_func_mode(dev);