perf evsel: No need to drag util/cgroup.h

The only thing we need is a forward declaration for 'struct cgroup_sel',
that is inside 'struct perf_evsel'.

Include cgroup.h instead on the tools that support cgroups.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-b7kuymbgf0zxi5viyjjtu5hk@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-record.c

@@ -15,6 +15,7 @@
 #include "util/parse-events.h"
 
 #include "util/callchain.h"
+#include "util/cgroup.h"
 #include "util/header.h"
 #include "util/event.h"
 #include "util/evlist.h"

tools/perf/builtin-stat.c

@@ -43,6 +43,7 @@
 
 #include "perf.h"
 #include "builtin.h"
+#include "util/cgroup.h"
 #include "util/util.h"
 #include "util/parse-options.h"
 #include "util/parse-events.h"

tools/perf/util/evsel.c

@@ -16,6 +16,7 @@
 #include <sys/resource.h>
 #include "asm/bug.h"
 #include "callchain.h"
+#include "cgroup.h"
 #include "evsel.h"
 #include "evlist.h"
 #include "util.h"

tools/perf/util/evsel.h

@@ -7,7 +7,6 @@
 #include <linux/perf_event.h>
 #include <linux/types.h>
 #include "xyarray.h"
-#include "cgroup.h"
 #include "symbol.h"
 
 struct perf_counts_values {
@@ -42,6 +41,8 @@ struct perf_sample_id {
 	u64			period;
 };
 
+struct cgroup_sel;
+
 /** struct perf_evsel - event selector
  *
  * @name - Can be set to retain the original event name passed by the user,