drm/mgag200: Use video aperture helpers

drm/mgag200: Use video aperture helpers

DRM's aperture functions have long been implemented as helpers
under drivers/video/ for use with fbdev. Avoid the DRM wrappers by
calling the video functions directly.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Jocelyn Falempe <jfalempe@redhat.com>
Acked-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240930130921.689876-11-tzimmermann@suse.de