drm/omap: drop omapdss-boot-init

The table of compatible values needed to be prefixed with "omapdss,"
is empty, so all of this code is doing nothing now. Let's drop it.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201215104657.802264-34-tomi.valkeinen@ti.com