trace-cmd: Compare index of events to proper end
trace-cmd: Compare index of events to proper end

The index is the offest from the end of the page, where as the
page_size attribute is the offset from the beginning of the data.
Fix the compare of the index and the page_size to compare at the
same starting point.

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

bigzz/trace-cmd,bigzz/trace-cmd