iommu/vt-d: Remove static identity map code

The code to prepare the static identity map for various reserved
memory ranges in intel_iommu_init() is duplicated with the default
domain mechanism now. Remove it to avoid duplication.

Signed-off-by: James Sewart <jamessewart@arista.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>