Add ocf_cache_set_flush_queue() function

This is needed to enable flushing with dynamic queues.

Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>

inc/ocf_cache.h

@@ -266,5 +266,12 @@ void ocf_cache_set_priv(ocf_cache_t cache, void *priv);
  */
 void *ocf_cache_get_priv(ocf_cache_t cache);
 
+/**
+ * @brief Set queue to be used during flush operation
+ *
+ * @param[in] cache Cache object
+ * @param[in] queue Queue object
+ */
+void ocf_cache_set_flush_queue(ocf_cache_t cache, ocf_queue_t queue);
 
 #endif /* __OCF_CACHE_H__ */