package/libseccomp: bump version to 2.2.0

- change upstream URL, project moved to github
- removed patches not needed anymore since project switched to autoconf
- add newly supported platforms to Config.in

[Thomas:
 - remove hash file, since we're fetching from github now.]

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>