anv: allow vkCmdPushDescriptorSetKHR with A64 messages
When vkCmdPushDescriptorSetKHR is used, the descriptor set is allocated internally without belonging to any pool. Such descriptor set will be visible on the GPU side because it's a part of the dynamic state stream, but we still have to store its address in the array of descriptor sets.
Complements: 379b9bb7 ("anv: Support fetching descriptor addresses from push constants")