sandbox: correct cpu nodes

The cpu nodes in arch/sandbox/dts/test.dts should conform to the devicetree
specification:

* property device_type must be set to "cpu"
* the reg property must be provided
* the cpu nodes must have an address

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/test/dm/timer.c b/test/dm/timer.c
index 70043b9..9f94d47 100644
--- a/test/dm/timer.c
+++ b/test/dm/timer.c
@@ -33,16 +33,16 @@
 {
 	struct udevice *dev;
 
-	cpu_sandbox_set_current("cpu-test1");
+	cpu_sandbox_set_current("cpu@1");
 	ut_assertok(uclass_get_device_by_name(UCLASS_TIMER, "timer@1", &dev));
 	ut_asserteq(3000000, timer_get_rate(dev));
 	ut_assertok(device_remove(dev, DM_REMOVE_NORMAL));
 
-	cpu_sandbox_set_current("cpu-test2");
+	cpu_sandbox_set_current("cpu@2");
 	ut_assertok(uclass_get_device_by_name(UCLASS_TIMER, "timer@1", &dev));
 	ut_asserteq(2000000, timer_get_rate(dev));
 
-	cpu_sandbox_set_current("cpu-test1");
+	cpu_sandbox_set_current("cpu@1");
 
 	return 0;
 }