wined3d: Add fall through comment in texture2d_blt_fbo() (Coverity).

Signed-off-by: Józef Kucia <jkucia@codeweavers.com>
Signed-off-by: Henri Verbeet <hverbeet@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>

dlls/wined3d/surface.c

@@ -175,6 +175,7 @@ static void texture2d_blt_fbo(const struct wined3d_device *device, struct wined3
 
         default:
             FIXME("Unsupported filter mode %s (%#x).\n", debug_d3dtexturefiltertype(filter), filter);
+            /* fall through */
         case WINED3D_TEXF_NONE:
         case WINED3D_TEXF_POINT:
             gl_filter = GL_NEAREST;