intel-iommu: Redefine macros to enable supporting 48 bit address width

intel-iommu: Redefine macros to enable supporting 48 bit address width

The current implementation of Intel IOMMU code only supports 39 bits
host/iova address width so number of macros use hard coded values based
on that. This patch is to redefine them so they can be used with
variable address widths. This patch doesn't add any new functionality
but enables adding support for 48 bit address width.

Signed-off-by: Prasad Singamsetty <prasad.singamsety@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>