drm/nouveau/secboot: support for r364 ACR

r364 is similar to r361, but uses a different hsflcn_desc structure to
introduce the shadow region address (even though it is not yet used by
this version).

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>