st/manager: update framebuffer size if texture has been resized

zink/kopper can and does expect this when resizing swapchains,
so don't ignore it

Reviewed-by: Adam Jackson <ajax@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14541>

src/mesa/state_tracker/st_manager.c

@@ -262,7 +262,9 @@ st_framebuffer_validate(struct gl_framebuffer *stfb,
 
       rb = stfb->Attachment[idx].Renderbuffer;
       assert(rb);
-      if (rb->texture == textures[i]) {
+      if (rb->texture == textures[i] &&
+          rb->Width == textures[i]->width0 &&
+          rb->Height == textures[i]->height0) {
          pipe_resource_reference(&textures[i], NULL);
          continue;
       }