Revert "dt: add of_alias_scan and of_alias_get_id"
This reverts commit 750f463a749e28464151ad26938d11b07b1c43cb.
of_alias_* still needs work to be generalized for 'promtree' dt
platforms, and to no implicitly create entries for available ids.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>