tools lib subcmd: Introduce OPTION_ULONG

tools lib subcmd: Introduce OPTION_ULONG

For completeness, will be used in 'perf trace --max-events'.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kim Phillips <kim.phillips@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-glaj3pwespxfj2fdjs9a20b6@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>