arm64: Pine64: update FDT files

The originally committed .dts files for the Pine64 were from an early
proof-of-concept version and should have never been committed upstream.
Replace them with much more mature versions, which also use a different
naming scheme.
Please note that at this point there is at least one binding which has
not been agreed upon, so this is subject to change.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>