iommu/amd: Remove old alias handling code

This mostly removes the code to create dev_data structures
for alias device ids. They are not necessary anymore, as
they were only created for device ids which have no struct
pci_dev associated with it.  But these device ids are
handled in a simpler way now, so there is no need for this
code anymore.

Signed-off-by: Joerg Roedel <jroedel@suse.de>