perf tool: Move pmus list variable to a new file

The 'pmus' list variable is defined as static variable under pmu.c file.

Introduce a new pmus.c file and migrate this variable to it. Also make
it non static so that it can be accessed from outside.

Suggested-by: Ian Rogers <[e-mail]>
Signed-off-by: Ravi Bangoria <[e-mail]>
Acked-by: Ian Rogers <[e-mail]>
Acked-by: Kan Liang <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Ananth Narayan <[e-mail]>
Cc: Athira Jajeev <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Kajol Jain <[e-mail]>
Cc: Leo Yan <[e-mail]>
Cc: Madhavan Srinivasan <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Sandipan Das <[e-mail]>
Cc: Santosh Shukla <[e-mail]>
Cc: Thomas Richter <[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/Build

···
 perf-y += parse-events-flex.o
 perf-y += parse-events-bison.o
 perf-y += pmu.o
+perf-y += pmus.o
 perf-y += pmu-flex.o
 perf-y += pmu-bison.o
 perf-y += pmu-hybrid.o

tools/perf/util/pmu.c

···
 #include "debug.h"
 #include "evsel.h"
 #include "pmu.h"
+#include "pmus.h"
 #include "parse-events.h"
 #include "print-events.h"
 #include "header.h"
···
 int perf_pmu_parse(struct list_head *list, char *name);
 extern FILE *perf_pmu_in;
 
-static LIST_HEAD(pmus);
 static bool hybrid_scanned;
 
 /*

tools/perf/util/pmus.c

···
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/list.h>
+#include <pmus.h>
+
+LIST_HEAD(pmus);

tools/perf/util/pmus.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __PMUS_H
+#define __PMUS_H
+
+extern struct list_head pmus;
+
+#define perf_pmus__for_each_pmu(pmu) list_for_each_entry(pmu, &pmus, list)
+
+#endif /* __PMUS_H */