fdt: Enable selecting correct DTB from appended FIT Image

This patch gives U-boot the runtime support to have the board specific
code decide which FDT to use. This is especially useful for devices
that need this type of runtime determination and also doesn't use SPL.

Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Reviewed-by: Lokesh Vutla <lokeshvutla@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

lib/fdtdec.c

@@ -4,6 +4,7 @@
  */
 
 #ifndef USE_HOSTCC
+#include <boot_fit.h>
 #include <common.h>
 #include <dm.h>
 #include <errno.h>
@@ -1221,6 +1222,15 @@ int fdtdec_setup(void)
 		gd->fdt_blob = (ulong *)&_image_binary_end;
 	else
 		gd->fdt_blob = (ulong *)&__bss_end;
+
+#  elif defined CONFIG_FIT_EMBED
+	gd->fdt_blob = locate_dtb_in_fit(&_end);
+
+	if (gd->fdt_blob == NULL || gd->fdt_blob <= ((void *)&_end)) {
+		puts("Failed to find proper dtb in embedded FIT Image\n");
+		return -1;
+	}
+
 #  else
 	/* FDT is at end of image */
 	gd->fdt_blob = (ulong *)&_end;