These directories were originally added as they were required for
spdxcheck.py, which upstream checkpatch.pl invokes.

As git doesn't index empty directories, they contained empty
.gitignore files. As these files were 0 bytes, make distclean now
removes them.

We already patch checkpatch.pl, so we will just patch spdxcheck.py
when we add it and get rid of these directories.
They can be added back should the need arise.

Reported-by: Geordan Neukum <gneukum1@gmail.com>
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>