include: add SPDX GPL-2.0-only license tags for files without licensing information ...

According to our /README, GPL-2.0-only applies for the whole project
except noted otherwise.

Signed-off-by: Roland Hieber <rohieb@rohieb.name>
Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

ubiformat: Allow to ubiformat with a buffer given ...

So far ubiformat can only handle files. Make it possible to pass
a buffer into ubiformat.

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

ubiformat: Add ubiformat write function ...

The ubiformat C API expects an image file as argument. With upcoming
Android fastboot sparse image support we can no longer provide a
complete image anymore. With this patch we can write an image in
multiple chunks after we've formatted a MTD device with ubiformat.

ubiformat_write will skip the EC header in both the MTD device we
write to and also the image we read from, so we can flash an image
on a MTD device containing EC headers already.

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

commands: ubiformat: move code to common/ ...

This is the final step to separate the ubiformat code from the
command. With this the ubiformat code gains a C API.

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