anv: Enable multi-layer aux-map init for HIZ+CCS
Fixes rendering corruption in the shadowmappingcascade Sascha Willems Vulkan demo. To see the corruption, I adjusted the demo options as follows:
- Enable "Display depth map"
- Set "Split lambda" to 0.100
- Make "Cascade" non-zero.
Fixes: 80ffbe91 ("anv: Add support for HiZ+CCS")