make pm4f be RGBA always, not pmcolor order

src/core/SkSpanProcs.cpp

Index: src/core/SkSpanProcs.cpp
diff --git a/src/core/SkSpanProcs.cpp b/src/core/SkSpanProcs.cpp
index efbce9704a8ceb35f48c696db069dd89d82388b7..385bd6b70fa8a37d9fca3d07197624d15aa06da7 100644
--- a/src/core/SkSpanProcs.cpp
+++ b/src/core/SkSpanProcs.cpp
@@ -22,7 +22,7 @@ static void load_l32(const SkPixmap& src, int x, int y, SkPM4f span[], int count
     SkASSERT(src.addr32(x + count - 1, y));
 
     for (int i = 0; i < count; ++i) {
-        (SkNx_cast<float>(Sk4b::Load(&addr[i])) * Sk4f(1.0f/255)).store(span[i].fVec);
+        (to_4f_rgba(addr[i]) * Sk4f(1.0f/255)).store(span[i].fVec);
     }
 }
 
@@ -32,7 +32,7 @@ static void load_s32(const SkPixmap& src, int x, int y, SkPM4f span[], int count
     SkASSERT(src.addr32(x + count - 1, y));
 
     for (int i = 0; i < count; ++i) {
-        srgb_to_linear(SkNx_cast<float>(Sk4b::Load(&addr[i])) * Sk4f(1.0f/255)).store(span[i].fVec);
+        srgb_to_linear(to_4f_rgba(addr[i]) * Sk4f(1.0f/255)).store(span[i].fVec);
     }
 }