tools/bpf: add unlimited rlimit for flow_dissector_load

tools/bpf: add unlimited rlimit for flow_dissector_load

On our test machine, bpf selftest test_flow_dissector.sh failed
with the following error:
  # ./test_flow_dissector.sh
  bpffs not mounted. Mounting...
  libbpf: failed to create map (name: 'jmp_table'): Operation not permitted
  libbpf: failed to load object 'bpf_flow.o'
  ./flow_dissector_load: bpf_prog_load bpf_flow.o
  selftests: test_flow_dissector [FAILED]

Let us increase the rlimit to remove the above map
creation failure.

Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>