tee: add OP-TEE driver

Adds a OP-TEE driver.

* Targets ARM and ARM64
* Supports using any U-Boot memory as shared memory
* Probes OP-TEE version using SMCs
* Uses OPTEE message protocol version 2 to communicate with secure world

Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Igor Opaniuk <igor.opaniuk@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/drivers/tee/optee/Makefile b/drivers/tee/optee/Makefile
new file mode 100644
index 0000000..6148feb
--- /dev/null
+++ b/drivers/tee/optee/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0+
+
+obj-y += core.o
+obj-y += supplicant.o