The new cgroup filter can take either of '==' or '!=' operator and a
pathname for the target cgroup.

  $ perf record -a --all-cgroups -e cycles --filter 'cgroup == /abc/def' -- sleep 1

Users should have --all-cgroups option in the command line to enable
cgroup filtering.  Technically it doesn't need to have the option as
it can get the current task's cgroup info directly from BPF.  But I want
to follow the convention for the other sample info.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20240826221045.1202305-4-namhyung@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>