perf trace: Fixup etcsnoop example

perf trace: Fixup etcsnoop example

Where we don't have "raw_syscalls:sys_enter", so we need to look for a
"*syscalls:sys_enter*" to initialize the offsets for the
__augmented_syscalls__ evsel, which is the case with etcsnoop, that was
segfaulting, fixed:

  # trace -e /home/acme/git/perf/tools/perf/examples/bpf/etcsnoop.c
     0.000 (         ): gnome-shell/2105 openat(dfd: CWD, filename: "/etc/localtime")                       ...
   631.834 (         ): cat/6521 openat(dfd: CWD, filename: "/etc/ld.so.cache", flags: RDONLY|CLOEXEC) ...
   632.637 (         ): bash/6521 openat(dfd: CWD, filename: "/etc/passwd")                          ...
  ^C#

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: b9b6a2ea2baf ("perf trace: Do not hardcode the size of the tracepoint common_ fields")
Link: https://lkml.kernel.org/n/tip-0tjwcit8qitsmh4nyvf2b0jo@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>