feat(handoff): port BL31-BL33 interface to fw handoff framework

The firmware handoff framework is a light weight mechanism for sharing
information between bootloader stages. Add support for this framework at
the handoff boundary between runtime firmware BL31 and NS software on FVP.

Change-Id: Ib02e0e4c20a39e32e06da667caf2ce5a28de1e28
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
diff --git a/plat/arm/board/fvp/platform.mk b/plat/arm/board/fvp/platform.mk
index 165b1610..5a0ed81 100644
--- a/plat/arm/board/fvp/platform.mk
+++ b/plat/arm/board/fvp/platform.mk
@@ -359,6 +359,10 @@
 $(eval $(call TOOL_ADD_PAYLOAD,${FVP_TOS_FW_CONFIG},--tos-fw-config,${FVP_TOS_FW_CONFIG}))
 endif
 
+ifeq (${TRANSFER_LIST}, 1)
+include lib/transfer_list/transfer_list.mk
+endif
+
 ifeq (${SPD},spmd)
 
 ifeq ($(ARM_SPMC_MANIFEST_DTS),)