anv: Disable the SMEM fallback for local memory

The fallback is incompatible with allocations that use CCS on XeHP. On
that platform, compression can't be used in SMEM.

Apps should be okay with this change. They're able to manage local and
system memory heaps directly (see VK_EXT_memory_budget).

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14431>

src/intel/vulkan/anv_allocator.c

@@ -1691,9 +1691,7 @@ anv_device_alloc_bo(struct anv_device *device,
       uint32_t nregions = 0;
 
       if (alloc_flags & ANV_BO_ALLOC_LOCAL_MEM) {
-         /* For vram allocation, still use system memory as a fallback. */
          regions[nregions++] = device->physical->vram.region;
-         regions[nregions++] = device->physical->sys.region;
       } else {
          regions[nregions++] = device->physical->sys.region;
       }