selftests: bonding: cause oops in bond_rr_gen_slave_id

This bonding selftest used to cause a kernel oops on aarch64
and should be architectures agnostic.

Signed-off-by: Jonathan Toppins <jtoppins@redhat.com>
Acked-by: Jay Vosburgh <jay.vosburgh@canonical.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>