SurfaceControl: Correct setMatrix parameter naming.

The first parameter dsdx controls the X scaling. The last parameter
is called dtdy but controls the Y scaling. Clearly this was meant to be
named dsdy. You can verify this with a quick look at Transaction_test.

Test: Tried various stuff, phone still works.
Change-Id: Ie9e898443350ffdcf227888a8d85efdbe1b6b033
diff --git a/include/gui/SurfaceControl.h b/include/gui/SurfaceControl.h
index 54c8fa9..99208b2 100644
--- a/include/gui/SurfaceControl.h
+++ b/include/gui/SurfaceControl.h
@@ -69,7 +69,7 @@
     status_t    setFlags(uint32_t flags, uint32_t mask);
     status_t    setTransparentRegionHint(const Region& transparent);
     status_t    setAlpha(float alpha=1.0f);
-    status_t    setMatrix(float dsdx, float dtdx, float dsdy, float dtdy);
+    status_t    setMatrix(float dsdx, float dtdx, float dtdy, float dsdy);
     status_t    setCrop(const Rect& crop);
     status_t    setFinalCrop(const Rect& crop);