mtk8173: Re-add the hello_world.git

Signed-off-by: Joakim Bech <joakim.bech@linaro.org>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/mt8173-evb.xml b/mt8173-evb.xml
index 972e0d7..37c11f5 100644
--- a/mt8173-evb.xml
+++ b/mt8173-evb.xml
@@ -24,6 +24,9 @@
 	<!-- Linux kernel -->
 	<project remote="linaro-swg" path="linux" name="linux.git" revision="optee" />
 
+	<!-- Hello world TA -->
+	<project remote="linaro-swg" path="hello_world" name="hello_world.git" />
+
 	<!-- Filesystem -->
 	<project remote="linaro-swg" path="gen_rootfs" name="gen_rootfs.git" />