tpm: Add Kconfig options for TPMs

Add new Kconfig options for TPMs in preparation for moving boards to use
Kconfig for TPM configuration.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Christophe Ricard<christophe-h.ricard@st.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
diff --git a/common/Kconfig b/common/Kconfig
index 88dc016..bacc4e0 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -625,4 +625,16 @@
 
 endmenu
 
+menu "Security commands"
+config CMD_TPM
+	bool "Enable the 'tpm' command"
+	depends on TPM
+	help
+	  This provides a means to talk to a TPM from the command line. A wide
+	  range of commands if provided - see 'tpm help' for details. The
+	  command requires a suitable TPM on your board and the correct driver
+	  must be enabled.
+
+endmenu
+
 endmenu