unix: add loong64 tag to endian_little.go

Updates golang/go#46229

Change-Id: I35b57e9158671b159a73b4eba4baa8bfebf2ce31
Reviewed-on: https://go-review.googlesource.com/c/sys/+/400774
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
diff --git a/unix/endian_little.go b/unix/endian_little.go
index 4362f47..b0f2bc4 100644
--- a/unix/endian_little.go
+++ b/unix/endian_little.go
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 //
-//go:build 386 || amd64 || amd64p32 || alpha || arm || arm64 || mipsle || mips64le || mips64p32le || nios2 || ppc64le || riscv || riscv64 || sh
-// +build 386 amd64 amd64p32 alpha arm arm64 mipsle mips64le mips64p32le nios2 ppc64le riscv riscv64 sh
+//go:build 386 || amd64 || amd64p32 || alpha || arm || arm64 || loong64 || mipsle || mips64le || mips64p32le || nios2 || ppc64le || riscv || riscv64 || sh
+// +build 386 amd64 amd64p32 alpha arm arm64 loong64 mipsle mips64le mips64p32le nios2 ppc64le riscv riscv64 sh
 
 package unix