This eliminates the following sparse warning:

init/main.c:306:6: warning: symbol 'xbc_namebuf' was not declared.
Should it be static?

Link: https://lkml.kernel.org/r/20200915070324.2239473-1-yanaijie@huawei.comReported-by: NHulk Robot <hulkci@huawei.com>
Acked-by: NMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>