The White Hawk CPU board can be used standalone, without connecting it
to the White Hawk BreakOut board.

Add a DTS file for supporting this use case.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/95ac53e7f2bc42402eb411ad7f64a66864a3de01.1706192990.git.geert+renesas@glider.be