venus: drop internal memory pools

This exists due to historical limitations which have long gone obsolete.
This persists longer due to hostorical perf issues that have recently
gone obsolete on the platforms shipping Venus. Meanwhile, clients like
skiavk and ANGLE nowadays do a better job managing suballocations. The
tiny perf win from having this giant internal pool has been beaten by
the memory waste, longer one-shot jank due to largier alloc, allocations
no need to be mapped but only because host-visible is advertised across
mem types and varies workarounds and markups needed to make alignment
work and make VVL happy. Dropping it also reduces the maintenance cost.

Signed-off-by: Yiwei Zhang <zzyiwei@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29362>

src/virtio/vulkan/vn_queue.c

@@ -516,7 +516,7 @@ vn_queue_submission_prepare(struct vn_queue_submission *submit)
          submit->submit_batches[0].pNext, WSI_MEMORY_SIGNAL_SUBMIT_INFO_MESA);
       if (info) {
          submit->wsi_mem = vn_device_memory_from_handle(info->memory);
-         assert(!submit->wsi_mem->base_memory && submit->wsi_mem->base_bo);
+         assert(submit->wsi_mem->base_bo);
       }
    }