arm: ti: Get the hwmods property either from the node or the parent

r350229 changed the code to lookup the ti,hwmods property in the parent
as it's now like that in the DTS from >= Linux 5.0, allow the property
to be also in the node itself so we can boot with an older DTB.

Reported by: "Dr. Rolf Jansen" <rj@obsigna.com>