tf_config: add TF config fragments

Signed-off-by: Fathi Boudra <fathi.boudra@linaro.org>
Change-Id: I9565147cbc333fbae01bc0e70cccc33b06c4faee
diff --git a/tf_config/fvp-default b/tf_config/fvp-default
new file mode 100644
index 0000000..1e9dfe2
--- /dev/null
+++ b/tf_config/fvp-default
@@ -0,0 +1,2 @@
+CROSS_COMPILE=aarch64-linux-gnu-
+PLAT=fvp