Revert of Code's more readable when SkPMFloat is an Sk4f.

src/opts/SkNx_sse.h

Index: src/opts/SkNx_sse.h
diff --git a/src/opts/SkNx_sse.h b/src/opts/SkNx_sse.h
index c1ae1f0469d0161578d1cc7d6b8b1a4930a46212..cae2d458f66b968621ee78d7abd2bbc01b23a2fc 100644
--- a/src/opts/SkNx_sse.h
+++ b/src/opts/SkNx_sse.h
@@ -146,6 +146,7 @@
     typedef SkNi<4, int32_t> Ni;
 public:
     SkNf(const __m128& vec) : fVec(vec) {}
+    __m128 vec() const { return fVec; }
 
     SkNf() {}
     explicit SkNf(float val)           : fVec( _mm_set1_ps(val) ) {}
@@ -181,7 +182,7 @@
         return pun.fs[k&3];
     }
 
-protected:
+private:
     __m128 fVec;
 };