spv: Remove peer disconnection logic

The p2p package already ensures peers are dropped if they are behind the
wallet's main chain tip height, therefore this check is redundant in the
spv syncer.

spv/sync.go

@@ -1495,6 +1495,9 @@ func (s *Syncer) getHeaders(ctx context.Context, rp *p2p.RemotePeer) error {
 
 		s.sidechainMu.Unlock()
 
+		// Any new peers should not be significantly behind the new tip.
+		s.setRequiredHeight(int32(tip.Header.Height))
+
 		// Generate new locators
 		s.locatorMu.Lock()
 		locators, err = s.wallet.BlockLocators(ctx, nil)
@@ -1509,13 +1512,6 @@ func (s *Syncer) getHeaders(ctx context.Context, rp *p2p.RemotePeer) error {
 }
 
 func (s *Syncer) startupSync(ctx context.Context, rp *p2p.RemotePeer) error {
-	// Disconnect from the peer if their advertised block height is
-	// significantly behind the wallet's.
-	_, tipHeight := s.wallet.MainChainTip(ctx)
-	if rp.InitialHeight() < tipHeight-6 {
-		return errors.E("peer is not synced")
-	}
-
 	// Continue with fetching headers only after missing cfilters have
 	// been fetched.
 	select {