perf stat: Fix a segfault with --per-cluster --metric-only

The new --per-cluster option was added recently but it forgot to update
the aggr_header fields which are used for --metric-only option.  And it
resulted in a segfault due to NULL string in fputs().

Fixes: cbc917a ("perf stat: Support per-cluster aggregation")
Reviewed-by: Yicong Yang <yangyicong@hisilicon.com>
Tested-by: Yicong Yang <yangyicong@hisilicon.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/r/20240628000604.1296808-1-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

Author: namhyung

tools/perf/util/stat-display.c

@@ -38,6 +38,7 @@
 static int aggr_header_lens[] = {
 	[AGGR_CORE] 	= 18,
 	[AGGR_CACHE]	= 22,
+	[AGGR_CLUSTER]	= 20,
 	[AGGR_DIE] 	= 12,
 	[AGGR_SOCKET] 	= 6,
 	[AGGR_NODE] 	= 6,
@@ -49,6 +50,7 @@ static int aggr_header_lens[] = {
 static const char *aggr_header_csv[] = {
 	[AGGR_CORE] 	= 	"core,cpus,",
 	[AGGR_CACHE]	= 	"cache,cpus,",
+	[AGGR_CLUSTER]	= 	"cluster,cpus,",
 	[AGGR_DIE] 	= 	"die,cpus,",
 	[AGGR_SOCKET] 	= 	"socket,cpus,",
 	[AGGR_NONE] 	= 	"cpu,",
@@ -60,6 +62,7 @@ static const char *aggr_header_csv[] = {
 static const char *aggr_header_std[] = {
 	[AGGR_CORE] 	= 	"core",
 	[AGGR_CACHE] 	= 	"cache",
+	[AGGR_CLUSTER]	= 	"cluster",
 	[AGGR_DIE] 	= 	"die",
 	[AGGR_SOCKET] 	= 	"socket",
 	[AGGR_NONE] 	= 	"cpu",