tools/kvm_stat: 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 comment in kvm_stat still refers to this older debugfs path, so let's
update it to avoid confusion.

Link: https://lkml.kernel.org/r/[e-mail]

Cc: "Tobin C. Harding" <[e-mail]>
Cc: Andrew Morton <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Masami Hiramatsu <[e-mail]>
Cc: Shuah Khan <[e-mail]>
Cc: Tycho Andersen <[e-mail]>
Acked-by: Paolo Bonzini <[e-mail]>
Reviewed-by: Steven Rostedt (Google) <[e-mail]>
Reviewed-by: Mukesh Ojha <[e-mail]>
Signed-off-by: Ross Zwisler <[e-mail]>
Signed-off-by: Steven Rostedt (Google) <[e-mail]>

tools/kvm/kvm_stat/kvm_stat

···
         name)'.
 
         All available events have directories under
-        /sys/kernel/debug/tracing/events/ which export information
+        /sys/kernel/tracing/events/ which export information
         about the specific event. Therefore, listing the dirs gives us
         a list of all available events.