tracing/user_events: Fix memory leak in user_event_create()

tracing/user_events: Fix memory leak in user_event_create()

Before current_user_event_group(), it has allocated memory and save it
in @name, this should freed before return error.

Link: https://lkml.kernel.org/r/20221115014445.158419-1-xiujianfeng@huawei.com
Fixes: e5d271812e7a ("tracing/user_events: Move pages/locks into groups to prepare for namespaces")
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>