perf s390-cpumsf: Remove unused struct

struct s390_cpumsf_synth was likely cargo culted from other auxtrace
examples. It has no users, so remove.

Reviewed-by: Adrian Hunter <[e-mail]>
Signed-off-by: Ian Rogers <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Anshuman Khandual <[e-mail]>
Cc: Athira Rajeev <[e-mail]>
Cc: Huacai Chen <[e-mail]>
Cc: Ilkka Koskinen <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: James Clark <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: John Garry <[e-mail]>
Cc: Jonathan Cameron <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Leo Yan <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Mike Leach <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Nick Desaulniers <[e-mail]>
Cc: Nick Terrell <[e-mail]>
Cc: Oliver Upton <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Song Liu <[e-mail]>
Cc: Sun Haiyong <[e-mail]>
Cc: Suzuki Poulouse <[e-mail]>
Cc: Will Deacon <[e-mail]>
Cc: Yanteng Si <[e-mail]>
Cc: Yicong Yang <[e-mail]>
Cc: [e-mail]
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/s390-cpumsf.c

···
 	return err;
 }
 
-struct s390_cpumsf_synth {
-	struct perf_tool cpumsf_tool;
-	struct perf_session *session;
-};
-
 static int
 s390_cpumsf_process_auxtrace_event(struct perf_session *session,
 				   union perf_event *event __maybe_unused,