MFC r320296, r328173: Update dtc(1)

MFC r320296, r328173: Update dtc(1)

MFC r320296 (manu): dtc: Update to upstream 9ce35ff8

 - Add "compatible with gpl dtc X.Y.Z" to version output so U-Boot doesn't complain
 - Fix cross reference node

This fixes some Allwinner DTS (and probably others).

MFC r328173: dtc(1): Update to upstream ea3c233

Highlights of this update:
- /__local_fixups__ is now generated to be GPL dtc and libfdt compliant
- Compiling with -@ will now cause dtc to assign phandles to all labelled
  nodes
- /include/ and /incbin/ now handle absolute paths correctly
- The manpage now has information about overlays, including how to apply
  them and how to generate them
- Syntactic sugar for overlays is now supported, allowing an overlay DTS
  like:

=
/dts-v1/;
/plugin/;

&foo {
    foo,status = "okay";
};
=

to generate a fragment targetting <&foo>.