Revert "argon2: add loong64 SIMD implementation"

This reverts CL 657795.

Reason for revert: Does not build on 1.23 or 1.24

For golang/go#73354.

Change-Id: I69498f24b57bd6650c9d1f4c755922cfaaba4a84
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/665555
Reviewed-by: abner chenc <chenguoqi@loongson.cn>
Auto-Submit: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>

Author: prattmic

argon2/blamka_loong64.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build (!amd64 && !loong64) || purego || !gc
+//go:build !amd64 || purego || !gc
 
 package argon2