omapfb: Add support for the ZOOM MDK LCD

Add glue to control the OMAP_LDP LCD as a frame buffer device
using the existing dispc.c driver under omapfb.

Patch updated for mainline kernel. Note that the
drivers/video/omap should be updated to pass omap_lcd_config
in platform_data. The patch should also be updated to compile
if twl4030 is not selected, and eventually to use the regulator
framework.

Fixed-by: Jarkko Nikula <jarkko.nikula@gmail.com>
Fixed-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Stanley.Miao <stanley.miao@windriver.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Imre Deak <imre.deak@nokia.com>