trace-cmd: Add top_instance helper functions

Instead of comparing directly to the top_instance object, add two
helper functions:

  is_top_instance(instance), which returns true if the given instance
            is the top_instance.

  no_top_instance(), which returns true if top instance isn't beeing used
            for the given trace.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
1 file changed