Remove unused DisplayInfo structure

Bug: 29044347
Change-Id: I5c2465719050c8727b0b48ef515ee79a24e3d65d
diff --git a/services/surfaceflinger/DisplayHardware/HWComposer.h b/services/surfaceflinger/DisplayHardware/HWComposer.h
index b88e250..1a2a153 100644
--- a/services/surfaceflinger/DisplayHardware/HWComposer.h
+++ b/services/surfaceflinger/DisplayHardware/HWComposer.h
@@ -137,15 +137,6 @@
 
     void setVsyncEnabled(int32_t disp, HWC2::Vsync enabled);
 
-    struct DisplayConfig {
-        uint32_t width;
-        uint32_t height;
-        float xdpi;
-        float ydpi;
-        nsecs_t refresh;
-        int colorTransform;
-    };
-
     // Query display parameters.  Pass in a display index (e.g.
     // HWC_DISPLAY_PRIMARY).
     nsecs_t getRefreshTimestamp(int32_t disp) const;