x86, AMD IOMMU: do runtime list initialization at compile time

This patch changes the list initialization for the iommu list and the unity map
list from runtime to compile time.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Cc: iommu@lists.linux-foundation.org
Cc: bhavna.sarathy@amd.com
Cc: robert.richter@amd.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>