sh: r2dplus: Enable OF control

Enable OF control for SH4 R2Dplus board. This is necessary, because
the PCI uclass is designed in a way that makes it depend on DT and
disallows instanciating devices without DT (e.g. with platdata).

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>