Remove empty newlines in #include blocks.

This makes clang-format useful on those.

Also add a bunch of forgotten transitive includes, which otherwise
prevented compilation.

src/citra/emu_window/emu_window_sdl2.h

@@ -5,7 +5,6 @@
 #pragma once
 
 #include <utility>
-
 #include "common/emu_window.h"
 
 struct SDL_Window;