perf trace: Add cmd string table to decode sys_bpf first arg

 # perf trace -e bpf perf record -e /tmp/foo.o -a
   362.779 (0.130 ms): perf/3451 bpf(cmd: PROG_LOAD, uattr: 0x7ffe9a6825d0, size: 48) = 3

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-2b0nknu53baz9e0wj4thcdd8@git.kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>