anv: Fix descriptor set clean-up on BO allocation failure

anv: Fix descriptor set clean-up on BO allocation failure

This was a bit of rebase fail when writing 682c81bdfb.  We stopped
freeing descriptor sets back to the pool and started calling
vk_object_base_finish.  This commit reverts a that hunk should have
never made its way into the final patch.

Fixes: 682c81bdfb "vulkan,anv: Add a base object struct type"
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Tested-by: Mark Janes <mark.a.janes@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5032>