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/libs/gui/SurfaceControl.cpp b/libs/gui/SurfaceControl.cpp
index 0362216..070a3c8 100644
--- a/libs/gui/SurfaceControl.cpp
+++ b/libs/gui/SurfaceControl.cpp
@@ -147,10 +147,10 @@
     if (err < 0) return err;
     return mClient->setAlpha(mHandle, alpha);
 }
-status_t SurfaceControl::setMatrix(float dsdx, float dtdx, float dsdy, float dtdy) {
+status_t SurfaceControl::setMatrix(float dsdx, float dtdx, float dtdy, float dsdy) {
     status_t err = validate();
     if (err < 0) return err;
-    return mClient->setMatrix(mHandle, dsdx, dtdx, dsdy, dtdy);
+    return mClient->setMatrix(mHandle, dsdx, dtdx, dtdy, dsdy);
 }
 status_t SurfaceControl::setCrop(const Rect& crop) {
     status_t err = validate();