Merge branch 'selftests-net-add-missing-gitignore-and-extra_clean-entries'

Javier Carrasco says:

====================
selftests: net: add missing gitignore and EXTRA_CLEAN entries.

This series is a cherry-pick on top of v6.12-rc1 from the one I sent
for selftests with other patches that were not net-related:

https://lore.kernel.org/all/20240925-selftests-gitignore-v3-0-9db896474170@gmail.com/

The patches have not been modified, and the Reviewed-by tags have
been kept.

v1: https://lore.kernel.org/20240930-net-selftests-gitignore-v1-0-65225a855946@gmail.com
====================

Link: https://patch.msgid.link/20241005-net-selftests-gitignore-v2-0-3a0b2876394a@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>