make pm4f be RGBA always, not pmcolor order

src/core/SkPM4fPriv.h

Index: src/core/SkPM4fPriv.h
diff --git a/src/core/SkPM4fPriv.h b/src/core/SkPM4fPriv.h
index b39891ea2082e929e74eb6322a398e9b89d70740..0326eaf33c516bb343995a73673678039766a799 100644
--- a/src/core/SkPM4fPriv.h
+++ b/src/core/SkPM4fPriv.h
@@ -5,9 +5,8 @@
  * found in the LICENSE file.
  */
 
-#include "SkPM4f.h"
 #include "SkColorPriv.h"
-#include "SkNx.h"
+#include "SkPM4f.h"
 
 static inline float get_alpha(const Sk4f& f4) {
     return f4[SkPM4f::A];
@@ -28,6 +27,10 @@ static inline Sk4f to_4f(uint32_t b4) {
     return SkNx_cast<float>(Sk4b::Load((const uint8_t*)&b4));
 }
 
+static inline Sk4f to_4f_rgba(uint32_t b4) {
+    return swizzle_rb_if_bgra(to_4f(b4));
+}
+
 static inline Sk4f srgb_to_linear(const Sk4f& s4) {
     return set_alpha(s4 * s4, get_alpha(s4));
 }