Drop -Wno-unused-parameter.

The only one left is libedify. Will handle that in a separate CL.

Test: mmma bootable/recovery
Change-Id: I732a5f85229da90fd767bee2e46c5c95f529c396
diff --git a/vr_ui.cpp b/vr_ui.cpp
index 07cc9da..a58c99e 100644
--- a/vr_ui.cpp
+++ b/vr_ui.cpp
@@ -53,7 +53,7 @@
   return y + 4;
 }
 
-void VrRecoveryUI::DrawHighlightBar(int x, int y, int width, int height) const {
+void VrRecoveryUI::DrawHighlightBar(int /* x */, int y, int /* width */, int height) const {
   gr_fill(kMarginWidth + kStereoOffset, y, ScreenWidth() - kMarginWidth + kStereoOffset, y + height);
   gr_fill(ScreenWidth() + kMarginWidth - kStereoOffset, y,
           gr_fb_width() - kMarginWidth - kStereoOffset, y + height);