SF: DisplayCommand.colorTransform is just a matrix

Remove the hint from DisplayCommand.colorTransform as currently
we only use ColorTransform::IDENTITY and ColorTransform::ARBITRARY_MATRIX,
which both can be expressed using a matrix.

Bug: 208879711
Test: VTS
Change-Id: I1c335647aabb7f89c2c89e54abfc839d10a659fb
diff --git a/services/surfaceflinger/DisplayHardware/HWC2.cpp b/services/surfaceflinger/DisplayHardware/HWC2.cpp
index b1f7808..3dcea61 100644
--- a/services/surfaceflinger/DisplayHardware/HWC2.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWC2.cpp
@@ -436,8 +436,8 @@
     return static_cast<Error>(intError);
 }
 
-Error Display::setColorTransform(const android::mat4& matrix, ColorTransform hint) {
-    auto intError = mComposer.setColorTransform(mId, matrix.asArray(), hint);
+Error Display::setColorTransform(const android::mat4& matrix) {
+    auto intError = mComposer.setColorTransform(mId, matrix.asArray());
     return static_cast<Error>(intError);
 }