fbdev/efifb: Remove PM for parent device

The EFI device has the correct parent device set. This allows Linux
to handle the power management internally. Hence, remove the manual
PM management for the parent device 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/20240212090736.11464-5-tzimmermann@suse.de