vbe: Add a new vbe command

Add a command to look at VBE methods and their status. Provide a test for
all of this as well.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/cmd/Kconfig b/cmd/Kconfig
index 7d19706..211ebe9 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -330,6 +330,16 @@
 	help
 	  Support booting RTEMS images via the bootm command.
 
+config CMD_VBE
+	bool "vbe - Verified Boot for Embedded"
+	depends on BOOTMETH_VBE
+	default y
+	help
+	  Provides various subcommands related to VBE, such as listing the
+	  available methods, looking at the state and changing which method
+	  is used to boot. Updating the parameters is not currently
+	  supported.
+
 config BOOTM_VXWORKS
 	bool "Support booting VxWorks OS images"
 	depends on CMD_BOOTM