ARM: rmobile: Enable MMC and USB DM on ULCB

Enable the MMC and USB DM on the board since it's the modern method
and now supported by the drivers.

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