kasan: Use kasan_md_unsupported() to check for invalid addresses

The subsequent assert verifies that the address is in the kernel map
anyway, and this removes uses of the MD DMAP_*_ADDRESS constants from MI
code.

This fixes the amd64 KASAN build after commit 4dd828c80828 ("amd64: add
kva_layout").

MFC after: 2 weeks

(cherry picked from commit 1f683624df878b2e4c0187137640bf2e6662c36f)