upl: Add a command

Add a 'upl' command to work with Universal Payload features. For now it
only supports reading and writing a handoff structure.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/cmd/Kconfig b/cmd/Kconfig
index 978f44e..8af136d 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -388,6 +388,13 @@
 	help
 	  Support reading NAND Seattle Image (SEAMA) images.
 
+config CMD_UPL
+	bool "upl - Universal Payload Specification"
+	help
+	  Provides commands to deal with UPL payloads and handoff information.
+	  U-Boot supports generating and accepting handoff information. The
+	  mkimage tool will eventually support creating payloads.
+
 config CMD_VBE
 	bool "vbe - Verified Boot for Embedded"
 	depends on BOOTMETH_VBE