Blitter: Do not override global screen pitch to use 8bpp blitter

8bpp blitter keep a point to pitch (default screen pitch)

src/gfx_func.h

@@ -227,19 +227,4 @@ inline int GetCharacterHeight(FontSize size)
 	return font_height_cache[size];
 }
 
-/* Scoped temporary screen pitch override */
-struct TemporaryScreenPitchOverride {
-	int old_pitch;
-
-	TemporaryScreenPitchOverride(int new_pitch) : old_pitch(_screen.pitch)
-	{
-		_screen.pitch = new_pitch;
-	}
-
-	~TemporaryScreenPitchOverride()
-	{
-		_screen.pitch = this->old_pitch;
-	}
-};
-
 #endif /* GFX_FUNC_H */