sknx refactoring

src/opts/SkXfermode_opts.h

Index: src/opts/SkXfermode_opts.h
diff --git a/src/opts/SkXfermode_opts.h b/src/opts/SkXfermode_opts.h
index 31817f5f618769387afe64b65785e7bbb55e7756..b049c6315c8415dc8cb15ee2136fd7f96fd33cbe 100644
--- a/src/opts/SkXfermode_opts.h
+++ b/src/opts/SkXfermode_opts.h
@@ -122,7 +122,7 @@ static inline Sk4f a_rgb(const Sk4f& a, const Sk4f& rgb) {
     return a * Sk4f(0,0,0,1) + rgb * Sk4f(1,1,1,0);
 }
 static inline Sk4f alphas(const Sk4f& f) {
-    return SkNx_dup<SK_A32_SHIFT/8>(f);
+    return f.kth<SK_A32_SHIFT/8>();
 }
 
 XFERMODE(ColorDodge) {