x11/nvidia-driver: Fix build after kva_layout

Commit 4dd828c808286 on main branch of src removed 2 macros,
DMAP_MIN_ADDRESS and DMAP_MAX_ADDRESS and require to use variables
(members of struct) kva_layout.dmap_low and kva_layout.dmap_high
respectively.

This broke builds of x11/nvidia-driver[-304|-340|-390|-470|-devel].
And the change is not planned for MFC (POLA violation).

Fix build by using new variables conditionally.

As there are around 10 days between usable latest bump at base
65ed1a035ceb8 and base 4dd828c808286, there are broken time window.

PR: 288236
Reviewed by: ashafer, kib

(cherry picked from commit 9302fb05a0c6599bbe8963ff5201fd3b99994535)