Currently, bpftool perf subcommand has typo with the help message.
    $ tools/bpf/bpftool/bpftool perf help
    Usage: bpftool perf { show | list }
           bpftool perf help }
Since this bpftool perf subcommand help message has the extra bracket,
this commit fix the typo by removing the extra bracket.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/r/20230811121603.17429-1-danieltimlee@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
 {
        fprintf(stderr,
                "Usage: %1$s %2$s { show | list }\n"
-               "       %1$s %2$s help }\n"
+               "       %1$s %2$s help\n"
                "\n"
                "       " HELP_SPEC_OPTIONS " }\n"
                "",