arm: dts: k3-am64: Move to OF_UPSTREAM

Enable OF_UPSTREAM for AM64-EVM and SK-AM64 boards. Remove DT files that
are now available in dts/upstream. Update the appended files based on
version of latest OF_UPSTREAM sync point (v6.7-rc7).

Signed-off-by: Andrew Davis <afd@ti.com>
14 files changed