intel-iommu: trivially inline context entry macros

Some macros were unused, so I just dropped them:

  context_fault_disable
  context_translation_type
  context_address_root
  context_address_width
  context_domain_id

Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>