tracing: Fix a compilation error without CONFIG_MODULES

There are some code which depends on CONFIG_MODULES. #ifdef
to enclose it.

Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/174230515367.2909896.8132122175220657625.stgit@mhiramat.tok.corp.google.com


Fixes: dca91c1c5468 ("tracing: Have persistent trace instances save module addresses")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>