perf test: Add AMD IBS sw filter test

perf test: Add AMD IBS sw filter test

The kernel v6.14 added 'swfilt' to support privilege filtering in
software so that IBS can be used by regular users.  Add a test case in
x86 to verify the behavior.

  $ sudo perf test -vv 'IBS software filter'
  113: AMD IBS software filtering:
  --- start ---
  test child forked, pid 178826
  check availability of IBS swfilt
  run perf record with modifier and swfilt
  [ perf record: Woken up 3 times to write data ]
  [ perf record: Captured and wrote 0.000 MB /dev/null ]
  [ perf record: Woken up 3 times to write data ]
  [ perf record: Captured and wrote 0.000 MB /dev/null ]
  [ perf record: Woken up 3 times to write data ]
  [ perf record: Captured and wrote 0.000 MB /dev/null ]
  [ perf record: Woken up 0 times to write data ]
  [ perf record: Captured and wrote 0.000 MB /dev/null ]
  check number of samples with swfilt
  [ perf record: Woken up 3 times to write data ]
  [ perf record: Captured and wrote 0.037 MB - ]
  [ perf record: Woken up 3 times to write data ]
  [ perf record: Captured and wrote 0.041 MB - ]
  ---- end(0) ----
  113: AMD IBS software filtering                                      : Ok

Reviewed-by: Ravi Bangoria <ravi.bangoria@amd.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> # On a 9950x3d
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>
Link: https://lore.kernel.org/r/20250524002754.1266681-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>