scripts/dtc: Update to upstream version 1.4.1

Includes the new localfixups format.

Signed-off-by: Phil Elwell <phil@raspberrypi.org>

scripts/dtc: Fix UMR causing corrupt dtbo overlay files

struct fixup_entry is allocated from the heap but it's member
local_fixup_generated was never initialized. This lead to
corrupted dtbo files.

Fix this by initializing local_fixup_generated to false.

Signed-off-by: Matthias Reichl <hias@horus.com>

scripts/dtc: Only emit local fixups for overlays

Signed-off-by: Phil Elwell <phil@raspberrypi.org>