OMAP: use dvi panel driver instead of generic-dpi

Multiple OMAP3/4 boards have a DVI framer output. This patch makes the
boards use the new panel-dvi driver, instead of the panel-generic-dpi
driver.

Separate drivers for fixed size panels and DVI framer gives us cleaner
driver code.

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