dm: test: Add "/firmware" node scan test

Add a test which verifies that all subnodes under "/firmware"
nodes are scanned.

Signed-off-by: Rajan Vaja <rajan.vaja@xilinx.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Added 'imply FIRMWARE' to sandbox Kconfig to fix test failures, fixed
ordering of lines in arch/sandbox/dts/test.dts and test/dm/Makefile,
updated #if condition in drivers/firmware/firmware-uclass.c:
Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/firmware/Makefile

@@ -1,3 +1,4 @@
 obj-$(CONFIG_FIRMWARE)		+= firmware-uclass.o
 obj-$(CONFIG_ARM_PSCI_FW)	+= psci.o
 obj-$(CONFIG_TI_SCI_PROTOCOL)	+= ti_sci.o
+obj-$(CONFIG_SANDBOX)		+= firmware-sandbox.o

drivers/firmware/firmware-sandbox.c

@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * sandbox firmware driver
+ *
+ * Copyright (C) 2018 Xilinx, Inc.
+ */
+
+#include <common.h>
+#include <dm.h>
+
+static const struct udevice_id generic_sandbox_firmware_ids[] = {
+	{ .compatible = "sandbox,firmware" },
+	{ }
+};
+
+U_BOOT_DRIVER(sandbox_firmware) = {
+	.name = "sandbox_firmware",
+	.id = UCLASS_FIRMWARE,
+	.of_match = generic_sandbox_firmware_ids,
+};

drivers/firmware/firmware-uclass.c

@@ -7,7 +7,7 @@
 UCLASS_DRIVER(firmware) = {
 	.id		= UCLASS_FIRMWARE,
 	.name		= "firmware",
-#if CONFIG_IS_ENABLED(OF_CONTROL)
+#if CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)
 	.post_bind	= dm_scan_fdt_dev,
 #endif
 };