trace-cmd: Use size of record to determine kernel stack trace
trace-cmd: Use size of record to determine kernel stack trace

The kernel stack trace may soon become dynamic, and the size
will depend on the size of the record and not the size of
the stack array. Use the size of the record to determine the
end of the stack output instead of the array.

Signed-off-by: Steven Rostedt <43232e92d70cc7aa53504ad0397085ee47bad87f@goodmis.org>

bigzz/trace-cmd,bigzz/trace-cmd