perf tools: Use __maybe_unused consistently

Instead of defining __unused or redefining __maybe_unused.

Cc: Adrian Hunter <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Wang Nan <[e-mail]>
Link: http://lkml.kernel.org/n/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/bench/numa.c

···
  * kernel (KSM, zero page, etc.) cannot optimize away RAM
  * accesses:
  */
-static inline u64 access_data(u64 *data __attribute__((unused)), u64 val)
+static inline u64 access_data(u64 *data, u64 val)
 {
 	if (g->p.data_reads)
 		val += *data;

tools/perf/jvmti/jvmti_agent.h

···
 #include <stdint.h>
 #include <jvmti.h>
 
-#define __unused __attribute__((unused))
-
 #if defined(__cplusplus)
 extern "C" {
 #endif

tools/perf/jvmti/libjvmti.c

···
+#include <linux/compiler.h>
 #include <sys/types.h>
 #include <stdio.h>
 #include <string.h>
···
 }
 
 JNIEXPORT jint JNICALL
-Agent_OnLoad(JavaVM *jvm, char *options, void *reserved __unused)
+Agent_OnLoad(JavaVM *jvm, char *options, void *reserved __maybe_unused)
 {
 	jvmtiEventCallbacks cb;
 	jvmtiCapabilities caps1;
···
 }
 
 JNIEXPORT void JNICALL
-Agent_OnUnload(JavaVM *jvm __unused)
+Agent_OnUnload(JavaVM *jvm __maybe_unused)
 {
 	int ret;
 

tools/perf/pmu-events/jevents.c

···
 #include "json.h"
 #include "jevents.h"
 
-#ifndef __maybe_unused
-#define __maybe_unused                  __attribute__((unused))
-#endif
-
 int verbose;
 char *prog;
 

tools/perf/util/evsel.c

···
 #include <traceevent/event-parse.h>
 #include <linux/hw_breakpoint.h>
 #include <linux/perf_event.h>
+#include <linux/compiler.h>
 #include <linux/err.h>
 #include <sys/ioctl.h>
 #include <sys/resource.h>
···
 }
 
 static int __open_attr__fprintf(FILE *fp, const char *name, const char *val,
-				void *priv __attribute__((unused)))
+				void *priv __maybe_unused)
 {
 	return fprintf(fp, "  %-32s %s\n", name, val);
 }

tools/perf/util/header.c

···
 #include <unistd.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <linux/compiler.h>
 #include <linux/list.h>
 #include <linux/kernel.h>
 #include <linux/bitops.h>
···
 }
 
 static int __desc_attr__fprintf(FILE *fp, const char *name, const char *val,
-				void *priv __attribute__((unused)))
+				void *priv __maybe_unused)
 {
 	return fprintf(fp, ", %s = %s", name, val);
 }