ngage: Remove Nokia N-Gage support.

This can be reverted if a toolchain arrives that can handle C99 features like
variables declared in the middle of a scope, but for now we literally can't
compile SDL3 for this platform.

Fixes #11243.

build-scripts/rename_macros.py

@@ -113,7 +113,6 @@ RENAMED_MACROS = {
     "__LINUX__": "SDL_PLATFORM_LINUX",
     "__OS2__": "SDL_PLATFORM_OS2",
     # "__ANDROID__": "SDL_PLATFORM_ANDROID,
-    "__NGAGE__": "SDL_PLATFORM_NGAGE",
     "__APPLE__": "SDL_PLATFORM_APPLE",
     "__TVOS__": "SDL_PLATFORM_TVOS",
     "__IPHONEOS__": "SDL_PLATFORM_IOS",