perf docs: Extend CAP_SYS_ADMIN with CAP_PERFMON where needed

Extend CAP_SYS_ADMIN with CAP_PERFMON in the docs.
Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-security-module@vger.kernel.org
Cc: selinux@vger.kernel.org
Link: http://lore.kernel.org/lkml/3b19cf79-f02d-04b4-b8b1-0039ac023b2c@linux.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-intel-pt.txt

@@ -687,7 +687,7 @@ The v4.2 kernel introduced support for a context switch metadata event,
 PERF_RECORD_SWITCH, which allows unprivileged users to see when their processes
 are scheduled out and in, just not by whom, which is left for the
 PERF_RECORD_SWITCH_CPU_WIDE, that is only accessible in system wide context,
-which in turn requires CAP_SYS_ADMIN.
+which in turn requires CAP_PERFMON or CAP_SYS_ADMIN.
 
 Please see the 45ac1403f564 ("perf: Add PERF_RECORD_SWITCH to indicate context
 switches") commit, that introduces these metadata events for further info.