nvk/descriptor_set: fix bo_size

This might not be correct, but it fixes
dEQP-VK.texture.*

src/nouveau/vulkan/nvk_descriptor_set.c

@@ -381,7 +381,7 @@ nvk_CreateDescriptorPool(VkDevice _device,
     * conservative here.)  Allocate enough extra space that we can chop it
     * into maxSets pieces and align each one of them to 32B.
     */
-   bo_size += NVK_MIN_UBO_ALIGNMENT * pCreateInfo->maxSets;
+   bo_size *= NVK_MIN_UBO_ALIGNMENT * pCreateInfo->maxSets;
 
    uint64_t entries_size = sizeof(struct nvk_descriptor_pool_entry) *
                            pCreateInfo->maxSets;