crypto/tls: rm marshalEncryptedClientHelloConfigList dead code

This package internal function has no call sites.

Change-Id: I262058199fd2f387ef3b5e21099421720cc5413e
Reviewed-on: https://go-review.googlesource.com/c/go/+/707815
TryBot-Bypass: Daniel McCarney <[email protected]>
Auto-Submit: Roland Shoemaker <[email protected]>
Auto-Submit: Daniel McCarney <[email protected]>
Reviewed-by: Carlos Amedee <[email protected]>
Reviewed-by: Roland Shoemaker <[email protected]>

Author: cpu

src/crypto/tls/ech.go

@@ -568,16 +568,6 @@ func parseECHExt(ext []byte) (echType echExtType, cs echCipher, configID uint8,
 	return echType, cs, configID, bytes.Clone(encap), bytes.Clone(payload), nil
 }
 
-func marshalEncryptedClientHelloConfigList(configs []EncryptedClientHelloKey) ([]byte, error) {
-	builder := cryptobyte.NewBuilder(nil)
-	builder.AddUint16LengthPrefixed(func(builder *cryptobyte.Builder) {
-		for _, c := range configs {
-			builder.AddBytes(c.Config)
-		}
-	})
-	return builder.Bytes()
-}
-
 func (c *Conn) processECHClientHello(outer *clientHelloMsg, echKeys []EncryptedClientHelloKey) (*clientHelloMsg, *echServerContext, error) {
 	echType, echCiphersuite, configID, encap, payload, err := parseECHExt(outer.encryptedClientHello)
 	if err != nil {