tracing: Pass the trace_array into ftrace_probe_ops functions

Pass the trace_array associated to a ftrace_probe_ops into the probe_ops
func(), init() and free() functions. The trace_array is the descriptor that
describes a tracing instance. This will help create the infrastructure that
will allow having function probes unique to tracing instances.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>