tracing: Adopt __free() and guard() for trace_fprobe.c

Adopt __free() and guard() for trace_fprobe.c to remove gotos.

Link: https://lore.kernel.org/173708043449.319651.12242878905778792182.stgit@mhiramat.roam.corp.google.com


Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>