fuse: Make fuse_args_to_req static

Fix sparse warning:

fs/fuse/dev.c:468:6: warning: symbol 'fuse_args_to_req' was not declared. Should it be static?
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Fixes: 68583165 ("fuse: add pages to fuse_args")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/fuse/dev.c

@@ -464,7 +464,7 @@ static void fuse_force_creds(struct fuse_conn *fc, struct fuse_req *req)
 	req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
 }
 
-void fuse_args_to_req(struct fuse_req *req, struct fuse_args *args)
+static void fuse_args_to_req(struct fuse_req *req, struct fuse_args *args)
 {
 	req->in.h.opcode = args->opcode;
 	req->in.h.nodeid = args->nodeid;