fdt: import bcm283x device tree sources from the linux kernel tree

This patch adds device trees for the bcm283x platform to be used with
OF_CONTROL. The version 4.8-rc7 of the linux kernel was used as source.

Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Signed-off-by: Fabian Vogt <fvogt@suse.com>
Reviewed-by: Simon Glass <sjg@chromium.org>