Sync tf_config files with internal CI

Signed-off-by: Zelalem <zelalem.aweke@arm.com>
Change-Id: I064f4f252fe7d3770719dee040feb96ea180a9bb
diff --git a/tf_config/juno-default-clang b/tf_config/juno-default-clang
new file mode 100644
index 0000000..b5f67ff
--- /dev/null
+++ b/tf_config/juno-default-clang
@@ -0,0 +1,3 @@
+CC=clang
+CROSS_COMPILE=aarch64-none-elf-
+PLAT=juno