nfsd: Remove write permission from file content

The write function doesn't be implemented in file content, and it's meaningless
to write data into this file directly. Remove write permission from it.

Signed-off-by: Yanchuan Nian <ycnian@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 9afa439..9f84703 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -1614,7 +1614,7 @@
 			goto out_nomem;
 	}
 	if (cd->cache_show) {
-		p = proc_create_data("content", S_IFREG|S_IRUSR|S_IWUSR,
+		p = proc_create_data("content", S_IFREG|S_IRUSR,
 				cd->u.procfs.proc_ent,
 				&content_file_operations_procfs, cd);
 		cd->u.procfs.content_ent = p;