kopper: invalidate drawables when resizing textures in place

this guarantees that swapchains shared between contexts will stay
in sync

Reviewed-by: Adam Jackson <ajax@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16351>

src/gallium/frontends/dri/kopper.c

@@ -559,6 +559,8 @@ kopper_allocate_textures(struct dri_context *ctx,
             if (drawable->textures[i] && i < ST_ATTACHMENT_DEPTH_STENCIL && !is_pixmap) {
                drawable->textures[i]->width0 = width;
                drawable->textures[i]->height0 = height;
+               /* force all contexts to revalidate framebuffer */
+               p_atomic_inc(&drawable->base.stamp);
             } else
                pipe_resource_reference(&drawable->textures[i], NULL);
             pipe_resource_reference(&drawable->msaa_textures[i], NULL);