crypto/{blake2b,blake2s,argon2,chacha20poly1305}: replace CPU feature detection

This change removes package specific CPU-feature detection code and
replaces it with x/sys/cpu.

Fixes golang/go#24843

Change-Id: I150dd7b3aeb8eef428c91f9b1df741ceb8a87a24
Reviewed-on: https://go-review.googlesource.com/110355
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

argon2/blamka_amd64.go

@@ -6,12 +6,11 @@
 
 package argon2
 
-func init() {
-	useSSE4 = supportsSSE4()
-}
+import "golang.org/x/sys/cpu"
 
-//go:noescape
-func supportsSSE4() bool
+func init() {
+	useSSE4 = cpu.X86.HasSSE41
+}
 
 //go:noescape
 func mixBlocksSSE2(out, a, b, c *block)

argon2/blamka_amd64.s

@@ -241,12 +241,3 @@ loop:
 	SUBQ  $2, BP
 	JA    loop
 	RET
-
-// func supportsSSE4() bool
-TEXT ·supportsSSE4(SB), 4, $0-1
-	MOVL $1, AX
-	CPUID
-	SHRL $19, CX       // Bit 19 indicates SSE4 support
-	ANDL $1, CX        // CX != 0 if support SSE4
-	MOVB CX, ret+0(FP)
-	RET