ARM: rmobile: Merge prior-stage firmware DT fragment into U-Boot DT on Gen3

The prior-stage firmware generates DT fragment containing the /firmware
node, /reserved-memory node and /memory@ nodes. Merge these nodes into
the U-Boot DT, so U-Boot can use this information.
Reviewed-by: NSimon Glass <sjg@chromium.org>
Signed-off-by: NMarek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Cc: Simon Glass <sjg@chromium.org>
Cc: Tom Rini <trini@konsulko.com>

board/renesas/rcar-common/common.c

@@ -21,32 +21,24 @@ DECLARE_GLOBAL_DATA_PTR;
 /* If the firmware passed a device tree use it for U-Boot DRAM setup. */
 extern u64 rcar_atf_boot_args[];
 
-int dram_init(void)
+int fdtdec_board_setup(const void *fdt_blob)
 {
-	const void *atf_fdt_blob = (const void *)(rcar_atf_boot_args[1]);
-	const void *blob;
+	void *atf_fdt_blob = (void *)(rcar_atf_boot_args[1]);
 
-	/* Check if ATF passed us DTB. If not, fall back to builtin DTB. */
 	if (fdt_magic(atf_fdt_blob) == FDT_MAGIC)
-		blob = atf_fdt_blob;
-	else
-		blob = gd->fdt_blob;
+		fdt_overlay_apply_node((void *)fdt_blob, 0, atf_fdt_blob, 0);
 
-	return fdtdec_setup_mem_size_base_fdt(blob);
+	return 0;
 }
 
-int dram_init_banksize(void)
+int dram_init(void)
 {
-	const void *atf_fdt_blob = (const void *)(rcar_atf_boot_args[1]);
-	const void *blob;
-
-	/* Check if ATF passed us DTB. If not, fall back to builtin DTB. */
-	if (fdt_magic(atf_fdt_blob) == FDT_MAGIC)
-		blob = atf_fdt_blob;
-	else
-		blob = gd->fdt_blob;
+	return fdtdec_setup_mem_size_base_fdt(gd->fdt_blob);
+}
 
-	fdtdec_setup_memory_banksize_fdt(blob);
+int dram_init_banksize(void)
+{
+	fdtdec_setup_memory_banksize_fdt(gd->fdt_blob);
 
 	return 0;
 }