cmd: add scmi command for SCMI firmware

This command, "scmi", may provide a command line interface to various SCMI
protocols. It supports at least initially SCMI base protocol and is
intended mainly for debug purpose.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Etienne Carriere <etienne.carriere@foss.st.com>
diff --git a/cmd/Kconfig b/cmd/Kconfig
index df6d71c..ca9f742 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -2559,6 +2559,15 @@
 	  a number of sub-commands for performing EC tasks such as
 	  updating its flash, accessing a small saved context area
 	  and talking to the I2C bus behind the EC (if there is one).
+
+config CMD_SCMI
+	bool "Enable scmi command"
+	depends on SCMI_FIRMWARE
+	default n
+	help
+	  This command provides user interfaces to several SCMI (System
+	  Control and Management Interface) protocols available on Arm
+	  platforms to manage system resources.
 endmenu
 
 menu "Filesystem commands"