iommu/dart: Move the blocked domain support to a global static

Move to the new static global for blocked domains. Move the blocked
specific code to apple_dart_attach_dev_blocked().

Reviewed-by: Janne Grunau <j@jannau.net>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Sven Peter <sven@svenpeter.dev>
Link: https://lore.kernel.org/r/6-v2-bff223cf6409+282-dart_paging_jgg@nvidia.com


Signed-off-by: Joerg Roedel <jroedel@suse.de>