video: Kconfig: Add a dependency to the Goldfish framebuffer driver

All other Goldfish drivers depend on GOLDFISH, I see no reason why the
framebuffer driver would be an exception.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>