arm: Remove TI code from GENERIC

TI support is in a sad state for years.
We haven't been able to keep up with all the breaking changes that
upstream do in the DTS. This requires a lot of new drivers to handle the
new buses that they create and all the new clocks that they expose.
Keep the code for now in case somebody is interested in reviving this
platform but stop bloating GENERIC with code that don't work.

Reviewed by: imp, mmel
MFC after: never
Sponsored by: Beckhoff Automation GmbH & Co. KG
Differential Revision: https://reviews.freebsd.org/D39843