env: export fdt_blob to the environment variable

Export fdt_blob to the environment variable. So that we may
use it to boot Linux.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Acked-by: Simon Glass <sjg@chromium.org>

common/board_r.c

@@ -446,6 +446,9 @@ static int initr_env(void)
 		env_relocate();
 	else
 		set_default_env(NULL);
+#ifdef CONFIG_OF_CONTROL
+	setenv_addr("fdtcontroladdr", gd->fdt_blob);
+#endif
 
 	/* Initialize from environment */
 	load_addr = getenv_ulong("loadaddr", 16, load_addr);