package/libbpf: security bump to version 1.6.0

The removed patch has been merged in version 1.6.0 fixing
the security CVE-2025-29481.

Fixes:
https://www.cve.org/CVERecord?id=CVE-2025-29481

Release notes:
https://github.com/libbpf/libbpf/releases/tag/v1.5.1
https://github.com/libbpf/libbpf/releases/tag/v1.6.0



Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>