ARM: OMAP: beagle: use new display drivers

Use the new display drivers for Beagleboard.

The new OMAP display drivers were merged for 3.11, and we can now change
the board files to use the new ones and phase out the old ones.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>