staging/fbtft: Initialize fb_op struct as static const

Replace dynamic allocation of the fb_ops instance with static
allocation. Initialize the fields at module-load time. The owner
field changes to THIS_MODULE, as in all other fbdev drivers.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230828132131.29295-8-tzimmermann@suse.de