chainntnfs: add block cache to NeutrinoNotifier

This commit adds gives BtcdNotifier access to the block cache and wraps
its GetBlock method so that the block cache's mutex map for the specific
hash is used.

chainreg/chainregistry.go

@@ -317,7 +317,7 @@ func NewChainControl(cfg *Config, blockCache *blockcache.BlockCache) (
 		// along with the wallet's ChainSource, which are all backed by
 		// the neutrino light client.
 		cc.ChainNotifier = neutrinonotify.New(
-			cfg.NeutrinoCS, hintCache, hintCache,
+			cfg.NeutrinoCS, hintCache, hintCache, blockCache,
 		)
 		cc.ChainView, err = chainview.NewCfFilteredChainView(
 			cfg.NeutrinoCS, blockCache,