bootstd: Allow enabling BOOTSTD_FULL without needing EXPO

It is sometimes useful to have one without the other, e.g. on a device
without a display, since at present the expo feature requires CONFIG_VIDEO
to be enabled.

Update the Makefile and bootflow command to support this, as well as the
EXPO dependency.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/boot/Kconfig b/boot/Kconfig
index fdcfbae..98e194f 100644
--- a/boot/Kconfig
+++ b/boot/Kconfig
@@ -561,6 +561,7 @@
 
 config EXPO
 	bool "Support for expos - groups of scenes displaying a UI"
+	depends on VIDEO
 	default y if BOOTMETH_VBE
 	help
 	  An expo is a way of presenting and collecting information from the
diff --git a/boot/Makefile b/boot/Makefile
index f990e66..43baf2b 100644
--- a/boot/Makefile
+++ b/boot/Makefile
@@ -30,7 +30,7 @@
 obj-$(CONFIG_$(SPL_TPL_)BOOTMETH_SCRIPT) += bootmeth_script.o
 ifdef CONFIG_$(SPL_TPL_)BOOTSTD_FULL
 obj-$(CONFIG_$(SPL_TPL_)CMD_BOOTEFI_BOOTMGR) += bootmeth_efi_mgr.o
-obj-$(CONFIG_$(SPL_TPL_)BOOTSTD) += bootflow_menu.o
+obj-$(CONFIG_$(SPL_TPL_)EXPO) += bootflow_menu.o
 endif
 
 obj-$(CONFIG_$(SPL_TPL_)OF_LIBFDT) += image-fdt.o
@@ -48,7 +48,7 @@
 obj-$(CONFIG_SPL_LOAD_FIT) += common_fit.o
 endif
 
-obj-$(CONFIG_$(SPL_TPL_)BOOTMETH_VBE) += expo.o scene.o scene_menu.o
+obj-$(CONFIG_$(SPL_TPL_)EXPO) += expo.o scene.o scene_menu.o
 
 obj-$(CONFIG_$(SPL_TPL_)BOOTMETH_VBE) += vbe.o vbe_request.o
 obj-$(CONFIG_$(SPL_TPL_)BOOTMETH_VBE_SIMPLE) += vbe_simple.o
diff --git a/cmd/bootflow.c b/cmd/bootflow.c
index 692bc6d..3548bbb 100644
--- a/cmd/bootflow.c
+++ b/cmd/bootflow.c
@@ -394,15 +394,20 @@
 	if (ret)
 		return CMD_RET_FAILURE;
 
-	ret = bootflow_menu_run(std, text_mode, &bflow);
-	if (ret) {
-		if (ret == -EAGAIN)
-			printf("Nothing chosen\n");
-		else
-			printf("Menu failed (err=%d)\n", ret);
-
-		return CMD_RET_FAILURE;
+	if (IS_ENABLED(CONFIG_EXPO)) {
+		ret = bootflow_menu_run(std, text_mode, &bflow);
+		if (ret) {
+			if (ret == -EAGAIN)
+				printf("Nothing chosen\n");
+			else
+				printf("Menu failed (err=%d)\n", ret);
+		}
+	} else {
+		printf("Menu not supported\n");
+		ret = -ENOSYS;
 	}
+	if (ret)
+		return CMD_RET_FAILURE;
 
 	printf("Selected: %s\n", bflow->os_name ? bflow->os_name : bflow->name);
 	std->cur_bootflow = bflow;