sdl: drop dead code

DisplayAllocator removal (commit
187cd1d9f30d13f0d0ef682e4d91cfa3e4cbd472) made this a nop.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

ui/sdl.c

diff --git a/ui/sdl.c b/ui/sdl.c
index 5baffa0..fc4dc1b 100644
--- a/ui/sdl.c
+++ b/ui/sdl.c
@@ -458,11 +458,6 @@
     }
     do_sdl_resize(width, height, bpp);
     scaling_active = 1;
-    if (!is_buffer_shared(ds->surface)) {
-        ds->surface = qemu_resize_displaysurface(ds, ds_get_width(ds),
-                                                 ds_get_height(ds));
-        dpy_gfx_resize(ds);
-    }
 }
 
 static void toggle_full_screen(DisplayState *ds)