feat(tsp): add ffa_helpers to enable more FF-A functionality

Include ffa_helpers originally taken from the TF-A Tests repo
to provide support for additional FF-A functionality.

Change-Id: Iacc3ee270d5e3903f86f8078ed915d1e791c1298
Signed-off-by: Marc Bonnici <marc.bonnici@arm.com>
Signed-off-by: Shruti Gupta <shruti.gupta@arm.com>
diff --git a/bl32/tsp/tsp.mk b/bl32/tsp/tsp.mk
index 3dfa802..c31b9b5 100644
--- a/bl32/tsp/tsp.mk
+++ b/bl32/tsp/tsp.mk
@@ -7,7 +7,8 @@
 INCLUDES		+=	-Iinclude/bl32/tsp
 
 ifeq (${SPMC_AT_EL3},1)
-   BL32_SOURCES            +=      bl32/tsp/tsp_ffa_main.c
+   BL32_SOURCES            +=      bl32/tsp/tsp_ffa_main.c                    \
+				   bl32/tsp/ffa_helpers.c
 else
    BL32_SOURCES            +=      bl32/tsp/tsp_main.c
 endif