kbuild: List libelf-devel as an alternative

On openSUSE, the libelf development files are in package libelf-devel.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Michal Marek <mmarek@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kbuild@vger.kernel.org
Link: http://lkml.kernel.org/n/tip-s8nyk3pyy2927sd7qp7u42oi@git.kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>