Switched _SOURCE to .gz, upstream does not provide bz2 tarballs anymore.
Fixes:
https://autobuild.buildroot.net/results/66ac5ae4b1cd053122ccebad9f61af02fa5fe7f6/
Co-developed-by: Bernd Kuhls <bernd@kuhls.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 4b33839f12)
Signed-off-by: Thomas Perale <thomas.perale@mind.be>