armv8: cavium: Add an implementation of ATF calling functions

This commit adds functions issuing calls to the product-specific ATF
services

Signed-off-by: Sergey Temerkhanov <s.temerkhanov@gmail.com>
Signed-off-by: Radha Mohan Chintakuntla <rchintakuntla@cavium.com>
diff --git a/board/cavium/thunderx/Makefile b/board/cavium/thunderx/Makefile
index 306044a..c78c414 100644
--- a/board/cavium/thunderx/Makefile
+++ b/board/cavium/thunderx/Makefile
@@ -5,4 +5,4 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-obj-y	:= thunderx.o
+obj-y	:= thunderx.o atf.o