linux-phytec-ti

selftests/bpf: rename flow dissector section to flow_dissector

Makes it compatible with the logic that derives program type
from section name in libbpf_prog_type_by_name.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>