fgraph: Remove redundant ftrace_graph_notrace_addr() test

We already have tested it before. The second one should be removed.
With this change, the performance should have little improvement.

Link: http://lkml.kernel.org/r/20190730140850.7927-1-changbin.du@gmail.com

Cc: stable@vger.kernel.org
Fixes: 9cd2992f

 ("fgraph: Have set_graph_notrace only affect function_graph tracer")
Signed-off-by: Changbin Du <changbin.du@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>