ftrace: Remove an unneeded condition

We know that "mod_matches" is true here so there is no need to check
again.

Link: http://lkml.kernel.org/r/20170331152130.GA4947@mwanda



Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>