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>

file_list: Add ubi flag ...

This flag is added to better support flashing UBI image with Android
sparse images. Android fastboot splits images which are bigger than the
free memory into multiple images which are then transferred in multiple
fastboot sessions. In a session which is not the first one we can no
longer detect if an image is a UBI image or not, so we need a flag to
make this explicit.

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

file_list: Add function to get entry by its name ...

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

file_list: Add function to add an entry to the list ...

Add file_list_add_entry() to add a single entry to a file_list. Then
use it in file_list_parse_one() instead of open coding adding a new
entry.

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

Add function to parse a string in dfu format ...

The dfu command parses a string which contains a list of
devices and flags. This format is useful for other users
aswell, so add common helper functions to parse it and
let the dfu command use this format.

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