dm: Add missing header files in lists and root

These files don't compile in some architectures. Fix it by adding the
missing headers.

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/core/lists.c

@@ -14,6 +14,7 @@
 #include <dm/platdata.h>
 #include <dm/uclass.h>
 #include <dm/util.h>
+#include <fdtdec.h>
 #include <linux/compiler.h>
 
 struct driver *lists_driver_lookup_name(const char *name)

drivers/core/root.c

@@ -10,6 +10,7 @@
 #include <common.h>
 #include <errno.h>
 #include <malloc.h>
+#include <libfdt.h>
 #include <dm/device.h>
 #include <dm/device-internal.h>
 #include <dm/lists.h>