Initialize HWC2On1Adapter with android_mode_t

Change-Id: I38726b5930927f9fe55e1433b74a6790f8813ec3
diff --git a/services/surfaceflinger/DisplayHardware/HWC2On1Adapter.cpp b/services/surfaceflinger/DisplayHardware/HWC2On1Adapter.cpp
index 8b29fa6..7bca0f1 100644
--- a/services/surfaceflinger/DisplayHardware/HWC2On1Adapter.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWC2On1Adapter.cpp
@@ -560,7 +560,7 @@
     mHwc1Id(-1),
     mConfigs(),
     mActiveConfig(nullptr),
-    mActiveColorMode(-1),
+    mActiveColorMode(static_cast<android_color_mode_t>(-1)),
     mName(),
     mType(type),
     mPowerMode(PowerMode::Off),