Reverse dependency between SkScalar.h and SkFixed.h.

The following are unused in Chromium, Android, Mozilla, and Google3:
 - SkFixedToScalar
 - SkScalarToFixed

The following are additionally unused in Skia:
 - SkStrAppendFixed
 - SkWriteBuffer::writeFixed

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1841123002

Review URL: https://codereview.chromium.org/1841123002
diff --git a/src/effects/SkDiscretePathEffect.cpp b/src/effects/SkDiscretePathEffect.cpp
index 5d5fc65..4525c1e 100644
--- a/src/effects/SkDiscretePathEffect.cpp
+++ b/src/effects/SkDiscretePathEffect.cpp
@@ -7,10 +7,11 @@
 
 
 #include "SkDiscretePathEffect.h"
-#include "SkReadBuffer.h"
-#include "SkWriteBuffer.h"
+#include "SkFixed.h"
 #include "SkPathMeasure.h"
+#include "SkReadBuffer.h"
 #include "SkStrokeRec.h"
+#include "SkWriteBuffer.h"
 
 sk_sp<SkPathEffect> SkDiscretePathEffect::Make(SkScalar segLength, SkScalar deviation,
                                                uint32_t seedAssist) {