dtc: Update update-dtc-source.sh from Linux ...

This updates update-dtc-source.sh from Linux-5.3-rc4.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

scripts/dtc: fix update-dtc-source.sh for barebox use ...

Unlike Linux:
- barebox' scripts/gen-dtb-s has a dependency on fdget,
  thus change the script to copy fdget.c as part of the update.
- has the libfdt source files in the same directory as the rest
- we don't have/need Makefile.libfdt

Adjust the update-dtc-source.sh script to account for this, so
it can be used to update the scripts/dtc directory. To do so, run
the script while its directory is otherwise empty.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

scripts/dtc: Update to upstream version 1.4.6 ...

Signed-off-by: Pascal Vizeli <pvizeli@syshack.ch>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

scripts/dtc: import update-dtc-source.sh from kernel v4.0-rc1 ...

The original script was written by Grant Likely <grant.likely@linaro.org>.
The version for barebox also imports some libfdt sources, so that we are
able to compile the fdtget host tool. Also remove the unused non-kconfig
makefiles.

Signed-off-by: Jan Luebbe <jlu@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>