Backout commit 83034612a883

This caused 8-bit modes to be chosen on older OS X releases.

Fixes Bugzilla #3000.

src/video/cocoa/SDL_cocoamodes.m

@@ -192,16 +192,9 @@ GetDisplayMode(_THIS, const void *moderef, CVDisplayLinkRef link, SDL_DisplayMod
         mode->format = SDL_PIXELFORMAT_ARGB8888;
         break;
     case 8: /* We don't support palettized modes now */
+    default: /* Totally unrecognizable bit depth. */
         SDL_free(data);
         return SDL_FALSE;
-    default:
-        /* Totally unrecognizable format. Maybe a new string reported by
-           CGDisplayModeCopyPixelEncoding() in a future platform SDK.
-           Just lie and call it 32-bit ARGB for now, so existing programs
-           don't completely fail on new setups. (most apps don't care about
-           the actual mode format anyhow.) */
-        mode->format = SDL_PIXELFORMAT_ARGB8888;
-        break;
     }
     mode->w = width;
     mode->h = height;