perf tools: Remove needless 'extern' from function prototypes

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-w246stf7ponfamclsai6b9zo@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/jit.h

@@ -3,13 +3,9 @@
 
 #include <data.h>
 
-extern int jit_process(struct perf_session *session,
-		       struct perf_data_file *output,
-		       struct machine *machine,
-		       char *filename,
-		       pid_t pid,
-		       u64 *nbytes);
+int jit_process(struct perf_session *session, struct perf_data_file *output,
+		struct machine *machine, char *filename, pid_t pid, u64 *nbytes);
 
-extern int jit_inject_record(const char *filename);
+int jit_inject_record(const char *filename);
 
 #endif /* __JIT_H__ */