plat: rcar: Pass DTB with DRAM layout from BL2 to next stages

Pass DTB containing DRAM layout from BL2 to BL33 via register x3, so
that the BL33 can simply consume it and get accurate DRAM layout info.
BL33 is in most usecases U-Boot.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
diff --git a/plat/renesas/rcar/platform.mk b/plat/renesas/rcar/platform.mk
index f7d6216..0cc746d 100644
--- a/plat/renesas/rcar/platform.mk
+++ b/plat/renesas/rcar/platform.mk
@@ -303,6 +303,7 @@
 include drivers/staging/renesas/rcar/ddr/ddr.mk
 include drivers/staging/renesas/rcar/qos/qos.mk
 include drivers/staging/renesas/rcar/pfc/pfc.mk
+include lib/libfdt/libfdt.mk
 
 PLAT_INCLUDES	:=	-Iinclude/common/tbbr			\
 			-Idrivers/staging/renesas/rcar/ddr	\
@@ -331,6 +332,7 @@
 BL2_SOURCES	+=	${RCAR_GIC_SOURCES}				\
 			lib/cpus/aarch64/cortex_a53.S			\
 			lib/cpus/aarch64/cortex_a57.S			\
+			${LIBFDT_SRCS}					\
 			common/desc_image_load.c			\
 			plat/renesas/rcar/aarch64/platform_common.c	\
 			plat/renesas/rcar/aarch64/plat_helpers.S	\