video/fbdev/68328fb: Remove dead code

This is dead code since 3.15. If their is no plan to
use it further, these can be removed forever.

Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Sabyasachi Gupta <sabyasachi.linux@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1567428544-8620-1-git-send-email-jrdr.linux@gmail.com