perf tools docs: Use canonical ftrace path

The canonical location for the tracefs filesystem is at /sys/kernel/tracing.

But, from Documentation/trace/ftrace.rst:

Before 4.1, all ftrace tracing control files were within the debugfs
file system, which is typically located at /sys/kernel/debug/tracing.
For backward compatibility, when mounting the debugfs file system,
the tracefs file system will be automatically mounted at:

/sys/kernel/debug/tracing

A few spots in the perf docs still refer to this older debugfs path, so
let's update them to avoid confusion.

Signed-off-by: Ross Zwisler <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Steven Rostedt (VMware) <[e-mail]>
Cc: [e-mail]
Link: http://lore.kernel.org/lkml/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/Documentation/perf-list.txt

···
 sysctl to -1, which allows non root to use these events.
 
 For accessing trace point events perf needs to have read access to
-/sys/kernel/debug/tracing, even when perf_event_paranoid is in a relaxed
+/sys/kernel/tracing, even when perf_event_paranoid is in a relaxed
 setting.
 
 TRACING

tools/perf/Documentation/perf-script-perl.txt

···
 the above option: -a to enable system-wide collection.
 
 The format file for the sched_wakeup event defines the following fields
-(see /sys/kernel/debug/tracing/events/sched/sched_wakeup/format):
+(see /sys/kernel/tracing/events/sched/sched_wakeup/format):
 
 ----
  format:

tools/perf/Documentation/perf-script-python.txt

···
 process can be generalized to any tracepoint or set of tracepoints
 you're interested in - basically find the tracepoint(s) you're
 interested in by looking at the list of available events shown by
-'perf list' and/or look in /sys/kernel/debug/tracing/events/ for
+'perf list' and/or look in /sys/kernel/tracing/events/ for
 detailed event and field info, record the corresponding trace data
 using 'perf record', passing it the list of interesting events,
 generate a skeleton script using 'perf script -g python' and modify the
···
 the above option: -a to enable system-wide collection.
 
 The format file for the sched_wakeup event defines the following fields
-(see /sys/kernel/debug/tracing/events/sched/sched_wakeup/format):
+(see /sys/kernel/tracing/events/sched/sched_wakeup/format):
 
 ----
  format: