Make sure some things are logged (#5515)

* sdl_impl.cpp: actually log the sdl error

* Log cpu slider and vsync

src/input_common/sdl/sdl_impl.cpp

@@ -470,7 +470,7 @@ SDLState::SDLState() {
         return;
     }
     if (SDL_SetHint(SDL_HINT_JOYSTICK_ALLOW_BACKGROUND_EVENTS, "1") == SDL_FALSE) {
-        LOG_ERROR(Input, "Failed to set Hint for background events", SDL_GetError());
+        LOG_ERROR(Input, "Failed to set Hint for background events: {}", SDL_GetError());
     }
 // these hints are only defined on sdl2.0.9 or higher
 #if SDL_VERSION_ATLEAST(2, 0, 9)