wayland: don't leak wl_fixes on uninit

I fixed this locally but forgot to push it before the original commit
got merged, oh well

Fixes: 6f6c29b0b4

video/out/wayland_common.c

@@ -4879,6 +4879,11 @@ void vo_wayland_uninit(struct vo *vo)
     if (wl->shm)
         wl_shm_destroy(wl->shm);
 
+#ifdef WL_FIXES_DESTROY
+    if (wl->fixes)
+        wl_fixes_destroy(wl->fixes);
+#endif
+
     if (wl->single_pixel_manager)
         wp_single_pixel_buffer_manager_v1_destroy(wl->single_pixel_manager);