crocus: Avoid replacing backing storage for buffers with no contents

Ported 97e9de1795 from iris

    We might get asked to pitch the storage on a buffer that already has
    no meaningful contents.  In this case, the existing buffer is as good
    as a new one.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11567>

src/gallium/drivers/crocus/crocus_resource.c

@@ -1130,6 +1130,10 @@ crocus_invalidate_resource(struct pipe_context *ctx,
    if (resource->target != PIPE_BUFFER)
       return;
 
+   /* If it's already invalidated, don't bother doing anything. */
+   if (res->valid_buffer_range.start > res->valid_buffer_range.end)
+      return;
+
    if (!resource_is_busy(ice, res)) {
       /* The resource is idle, so just mark that it contains no data and
        * keep using the same underlying buffer object.