perf tools: Add CAP_SYSLOG define for older systems

Some of the systems I test don't have that define, provide it
conditionally since we'll use it in the kptr_restrict checks in the next
patch.

Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Igor Lubashev <ilubashe@akamai.com>
Cc: James Morris <jmorris@namei.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Link: https://lkml.kernel.org/n/tip-dcize2v6jjab7tds5ngz97dk@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/cap.h

@@ -24,4 +24,9 @@ static inline bool perf_cap__capable(int cap __maybe_unused)
 
 #endif /* HAVE_LIBCAP_SUPPORT */
 
+/* For older systems */
+#ifndef CAP_SYSLOG
+#define CAP_SYSLOG	34
+#endif
+
 #endif /* __PERF_CAP_H */