Revert "ANDROID: of/property: Add device link support for iommus"

This reverts commit 87337fb7.

The patch I sent upstream to add iommu support is nicer than this and
also adds mboxes and io-channels support. So just revert this and pull
in the upstream patches to avoid conflicts and pull in support for
mboxes and io-channels.

Change-Id: I98ef50eb5cff310a5717d0fb78eceb04ff2510ec
Signed-off-by: Saravana Kannan <saravanak@google.com>