asahi: Assert we don't transition shared resources

This is an invariant maintained by all current callers and subtly required for
the BO swapping to work. Assert it to make it obvious.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23998>

src/gallium/drivers/asahi/agx_pipe.c

@@ -1077,6 +1077,7 @@ transition_resource(struct pipe_context *pctx, struct agx_resource *rsrc,
       agx_resource(pctx->screen->resource_create(pctx->screen, templ));
 
    assert(new_res);
+   assert(!(rsrc->base.bind & PIPE_BIND_SHARED) && "cannot swap BOs if shared");
 
    int level;
    BITSET_FOREACH_SET(level, rsrc->data_valid, PIPE_MAX_TEXTURE_LEVELS) {