perf-security: document perf_events/Perf resource control

Extend perf-security.rst file with perf_events/Perf resource control
section describing RLIMIT_NOFILE and perf_event_mlock_kb settings for
performance monitoring user processes.

Signed-off-by: Alexey Budankov <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>
1 file changed