OMAP: use generic DPI panel driver in board files

Still keep sharp_ls_panel, since the sharp_ls_panel driver contains blacklight
control driver code which will be moved out later. Then we can use generic DPI
driver for sharp_ls_panel.

Signed-off-by: Bryan Wu <bryan.wu@canonical.com>
Acked-by: Archit Taneja <archit@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>