nil: Fix image align and size constraints

In order to use compressed images we have to align to at least (1<<16)
though the kernel also likes (1<<21).

This fixes the alignments/sizes so they can work with vm allocs

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24326>

src/nouveau/nil/nil_image.c

@@ -439,6 +439,11 @@ nil_image_init(struct nv_device_info *dev,
    image->pte_kind = nil_choose_pte_kind(dev, info->format, info->samples,
                                          true /* TODO: compressed */);
 
+   image->align_B = MAX2(image->align_B, 4096);
+   if (image->pte_kind >= 0xb && image->pte_kind <= 0xe)
+      image->align_B = MAX2(image->align_B, (1 << 16));
+
+   image->size_B = ALIGN(image->size_B, image->align_B);
    return true;
 }