tracing/kprobes: Fix to free objects when failed to copy a symbol

In __trace_kprobe_create(), if something fails it must goto error block
to free objects. But when strdup() a symbol, it returns without that.
Fix it to goto the error block to free objects correctly.

Link: https://lore.kernel.org/all/173643297743.1514810.2408159540454241947.stgit@devnote2/



Fixes: 6212dd29 ("tracing/kprobes: Use dyn_event framework for kprobe events")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>