feat(fvp): add Dualroot CoT in DTB support

Adding support for Dualroot CoT in DTB. This makes it possible for BL2
to retrieve its chain of trust description from a configuration file in
DTB format. With this, the CoT description may be updated without
rebuilding BL2 image.

This feature can be enabled by building BL2 with COT_DESC_IN_DTB=1 and
COT=dualroot. The default behavior remains to embed the CoT description
into BL2 image.

Change-Id: I343931b145aa8a53b0a5d4b8aefb273ffb5a9163
Signed-off-by: Lauren Wehrmeister <lauren.wehrmeister@arm.com>
diff --git a/plat/arm/board/fvp/fdts/fvp_tb_fw_config.dts b/plat/arm/board/fvp/fdts/fvp_tb_fw_config.dts
index 9eb2177..ed60203 100644
--- a/plat/arm/board/fvp/fdts/fvp_tb_fw_config.dts
+++ b/plat/arm/board/fvp/fdts/fvp_tb_fw_config.dts
@@ -106,6 +106,8 @@
 #if COT_DESC_IN_DTB
 	#if defined(ARM_COT_cca)
 		#include "cca_cot_descriptors.dtsi"
+	#elif defined(ARM_COT_dualroot)
+		#include "dualroot_cot_descriptors.dtsi"
 	#elif defined(ARM_COT_tbbr)
 		#include "tbbr_cot_descriptors.dtsi"
 	#endif