dts: Revert DTS for OMAP family
In DTS import from Linux 5.5 the ti,hwmods were deprecated in favor of
using ti-sysc interconnect target module to identify the IP blocks.

Direct commit to stable/12, since stable/13 and later have an updated
ti-sysc driver.

Approved by: manu (mentor)
Differential revision: https://reviews.freebsd.org/D26552