9p: make v9fs_cache_inode_{get,put,set}_cookie empty inlines for !9P_CACHEFS

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/9p/cache.h b/fs/9p/cache.h
index 40cc54c..2f96754 100644
--- a/fs/9p/cache.h
+++ b/fs/9p/cache.h
@@ -101,6 +101,18 @@
 
 #else /* CONFIG_9P_FSCACHE */
 
+static inline void v9fs_cache_inode_get_cookie(struct inode *inode)
+{
+}
+
+static inline void v9fs_cache_inode_put_cookie(struct inode *inode)
+{
+}
+
+static inline void v9fs_cache_inode_set_cookie(struct inode *inode, struct file *file)
+{
+}
+
 static inline int v9fs_fscache_release_page(struct page *page,
 					    gfp_t gfp) {
 	return 1;