tracing: fprobe: Fix to remove recorded module addresses from filter

Even if there is a memory allocation failure in fprobe_addr_list_add(),
there is a partial list of module addresses. So remove the recorded
addresses from filter if exists.
This also removes the redundant ret local variable.

Fixes: a3dc2983 ("tracing: fprobe: Cleanup fprobe hash when module unloading")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Reviewed-by: Menglong Dong <menglong8.dong@gmail.com>