vulkan: Relax bda assert for zero-size buffers

Fixes: 73da18b956 ("vulkan: Add device address helpers to vk_buffer")
Reviewed-by: Faith Ekstrand <faith.ekstrand@collabora.com>
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33988>

src/vulkan/runtime/vk_buffer.h

@@ -68,7 +68,7 @@ static inline VkDeviceAddress
 vk_buffer_address(const struct vk_buffer *buffer,
                   VkDeviceSize offset)
 {
-   assert(buffer->device_address != 0);
+   assert(buffer->size == 0 || buffer->device_address != 0);
    return buffer->device_address + offset;
 }