perf pmu: Add a perf_pmu__fake object to use with __parse_events()

When wanting to use the support in __parse_events() for fake pmus, just
pass it.

Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/pmu.c

@@ -26,6 +26,8 @@
 #include "strbuf.h"
 #include "fncache.h"
 
+struct perf_pmu perf_pmu__fake;
+
 struct perf_pmu_format {
 	char *name;
 	int value;

tools/perf/util/pmu.h

@@ -43,6 +43,8 @@ struct perf_pmu {
 	struct list_head list;    /* ELEM */
 };
 
+extern struct perf_pmu perf_pmu__fake;
+
 struct perf_pmu_info {
 	const char *unit;
 	const char *metric_expr;