arm: configs: spear6xx: Enable PL110 display controller

Enable the PL110 DRM driver, used by the spear600.

Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>