Revert of Expand _01 half<->float limitation to _finite. Simplify.

src/core/SkMipMap.cpp

Index: src/core/SkMipMap.cpp
diff --git a/src/core/SkMipMap.cpp b/src/core/SkMipMap.cpp
index 4811c9e07394f9f6cb478da50014ca49d36b53c5..f469762ebac872f988ecf55aac5a0f53cbd30576 100644
--- a/src/core/SkMipMap.cpp
+++ b/src/core/SkMipMap.cpp
@@ -85,10 +85,10 @@
 struct ColorTypeFilter_F16 {
     typedef uint64_t Type; // SkHalf x4
     static Sk4f Expand(uint64_t x) {
-        return SkHalfToFloat_finite(x);
+        return SkHalfToFloat_01(x);
     }
     static uint64_t Compact(const Sk4f& x) {
-        return SkFloatToHalf_finite(x);
+        return SkFloatToHalf_01(x);
     }
 };