OMAPDSS: remove all old panel drivers

The board files now use the new panel drivers, making the old panel
drivers obsolete.

Remove the old panel drivers, Kconfig and Makefile entries, and the
panels' platform data structs.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Archit Taneja <archit@ti.com>