tee: optee: support AVB trusted application

Adds configuration option OPTEE_TA_AVB and a header file describing the
interface to the Android Verified Boot 2.0 (AVB) trusted application
provided by OP-TEE.

Tested-by: Igor Opaniuk <igor.opaniuk@linaro.org>
Reviewed-by: Igor Opaniuk <igor.opaniuk@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/tee/optee/Kconfig b/drivers/tee/optee/Kconfig
index 7484e6f..dbfa784 100644
--- a/drivers/tee/optee/Kconfig
+++ b/drivers/tee/optee/Kconfig
@@ -9,3 +9,19 @@
 	  mechanism. This driver can request services from OP-TEE, but also
 	  handle Remote Procedure Calls (RPC) from OP-TEE needed to
 	  execute a service. For more information see: https://www.op-tee.org
+
+if OPTEE
+
+menu "OP-TEE options"
+
+config OPTEE_TA_AVB
+	bool "Support AVB TA"
+	default y
+	help
+	  Enables support for the AVB Trusted Application (TA) in OP-TEE.
+	  The TA can support the "avb" subcommands "read_rb", "write"rb"
+	  and "is_unlocked".
+
+endmenu
+
+endif