ssh: remove Go 1.24 build tag for ML-KEM kex

Change-Id: Ia77ad1b6fef9919ab100fb10c42231725eb81c12
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/698775
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Nicola Murino <nicola.murino@gmail.com>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Roland Shoemaker <roland@golang.org>

ssh/mlkem.go

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build go1.24
-
 package ssh
 
 import (
@@ -13,23 +11,10 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"runtime"
-	"slices"
 
 	"golang.org/x/crypto/curve25519"
 )
 
-func init() {
-	// After Go 1.24rc1 mlkem swapped the order of return values of Encapsulate.
-	// See #70950.
-	if runtime.Version() == "go1.24rc1" {
-		return
-	}
-	supportedKexAlgos = slices.Insert(supportedKexAlgos, 0, KeyExchangeMLKEM768X25519)
-	defaultKexAlgos = slices.Insert(defaultKexAlgos, 0, KeyExchangeMLKEM768X25519)
-	kexAlgoMap[KeyExchangeMLKEM768X25519] = &mlkem768WithCurve25519sha256{}
-}
-
 // mlkem768WithCurve25519sha256 implements the hybrid ML-KEM768 with
 // curve25519-sha256 key exchange method, as described by
 // draft-kampanakis-curdle-ssh-pq-ke-05 section 2.3.3.