fscache, cachefiles: remove redundant variable 'cache'

Variable 'cache' is being assigned but is never used hence it is
redundant and can be removed.

Cleans up clang warning:
warning: variable 'cache' set but not used [-Wunused-but-set-variable]
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David Howells <dhowells@redhat.com>

fs/cachefiles/rdwr.c

@@ -968,11 +968,8 @@ void cachefiles_uncache_page(struct fscache_object *_object, struct page *page)
 	__releases(&object->fscache.cookie->lock)
 {
 	struct cachefiles_object *object;
-	struct cachefiles_cache *cache;
 
 	object = container_of(_object, struct cachefiles_object, fscache);
-	cache = container_of(object->fscache.cache,
-			     struct cachefiles_cache, cache);
 
 	_enter("%p,{%lu}", object, page->index);