iommu/amd: Convert IOMMUv2 state_table into state_list

The state_table consumes 512kb of memory and is only sparsly
populated. Convert it into a list to save memory. There
should be no measurable performance impact.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Tested-by: Jay Cornwall <Jay.Cornwall@amd.com>