Add DTS file for Armada 385 DB-AP board

Armada38x is already supported in the tree.
This commit adds support for DB-AP board.
File was taken from Linux v4.8 and accustomed to FreeBSD
in minimal possible way.

Submitted by: Bartosz Szczepanek <bsz@semihalf.com>
Obtained from: Semihalf
Sponsored by: Stormshield
Differential revision: https://reviews.freebsd.org/D7327