OMAPFB: Remove OMAP2/3 support from old omapfb driver

Old omapfb driver (drivers/video/omap/) is no longer used for OMAP2+
devices, and thus we can remove OMAP2+ support from it and make it an
OMAP1 omapfb driver.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>