ARM: dove: add initial DT file for Globalscale D2Plug

This adds an initial DT file for the Globalscale D2Plug with Dove SoC.
Currently, one LED is missing and I have not been able to get SD8787 driver
working. Those will be taken care of later.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>