build: remove go-fuzz dependency and references

We don't need go-fuzz now that we use native fuzzing.

build/dependencies.go

@@ -3,7 +3,7 @@
 
 package build
 
-// This file is a workaround to make sure go mod keeps around the btcd and fuzz
+// This file is a workaround to make sure go mod keeps around the btcd
 // dependencies in the go.sum file that we only use during certain tasks (such
 // as integration tests or fuzzing) or only for certain operating systems. For
 // example, the specific btcd import makes sure the indirect dependency
@@ -11,5 +11,4 @@ package build
 // tag, this dependency never ends up in the final lnd binary.
 import (
 	_ "github.com/btcsuite/btcd"
-	_ "github.com/dvyukov/go-fuzz/go-fuzz-dep"
 )