tests: add OP-TEE test suite

OP-TEE can get supplied with a devicetree and will then insert
its firmware node and reserved-memory sections into it.
As this devicetree often is not the one supplied to a later
loaded kernel, a previous commit added functionality to transfer
these nodes onto that new devicetree.

To make sure this functionality stays intact, also add a test
for the transfer functionality.

Signed-off-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/Makefile b/Makefile
index a9a78c3..3e0cbd9 100644
--- a/Makefile
+++ b/Makefile
@@ -751,6 +751,7 @@
 libs-$(CONFIG_HAS_POST) += post/
 libs-$(CONFIG_UNIT_TEST) += test/ test/dm/
 libs-$(CONFIG_UT_ENV) += test/env/
+libs-$(CONFIG_UT_OPTEE) += test/optee/
 libs-$(CONFIG_UT_OVERLAY) += test/overlay/
 
 libs-y += $(if $(BOARDDIR),board/$(BOARDDIR)/)