[BUG] GHASH逻辑错误造成GCM模式下tag错误

[wond4]

近期在做国密密码机对接，发现 sm4 库 gcm 模式下计算出的密文和密码机一致，但是鉴别TAG不同。
系统测试后发现密码机、GmSSL和在线验证结果一致，基本确定本库实现有问题。验证截图如下：

[wond4]

测试代码如下：

func Demo() {
	keyHex := "0123456789ABCDEFFEDCBA9876543210"
	plainHex := "AAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBCCCCCCCCCCCCCCCCDDDDDDDDDDDDDDDDEEEEEEEEEEEEEEEEFFFFFFFFFFFFFFFFEEEEEEEEEEEEEEEEAAAAAAAAAAAAAAAA"
	ivHex := "00001234567800000000ABCD"
	aadHex := "FEEDFACEDEADBEEFFEEDFACEDEADBEEFABADDAD2"

	keyBytes, _ := hex.DecodeString(keyHex)
	ivBytes, _ := hex.DecodeString(ivHex)
	aadBytes, _ := hex.DecodeString(aadHex)
	plainBytes, _ := hex.DecodeString(plainHex)
	cipherBytes, tagBytes := sm4.GCMEncrypt(keyBytes, ivBytes, plainBytes, aadBytes)
	log.Println("key in hex:", keyHex)
	log.Println("plain text in hex:", plainHex)
	log.Println("iv in hex:", ivHex)
	log.Println("aad in hex:", aadHex)
	log.Println("cipher text in hex:", hex.EncodeToString(cipherBytes))
	log.Println("tag in hex:", hex.EncodeToString(tagBytes))
}

[emmansun]

和#172 #198 类似