fbdev/efifb: Do not track parent device status

There will be no EFI framebuffer device for disabled parent devices
and thus we never probe efifb in that case. Hence remove the tracking
code from efifb.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240212090736.11464-7-tzimmermann@suse.de