drm/omap: Fix kernel docs

Fix doc related warnings seen with W=1: the function names have changed
but the docs have not been changed accordingly.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220916082206.167427-2-tomi.valkeinen@ideasonboard.com


Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>