nubus: Remove cast to void pointer

Casting void pointers to other pointer types is unnecessary.

Signed-off-by: Himanshu Jha <himanshujha199640@gmail.com>
Link: https://lore.kernel.org/r/1503819148-11676-1-git-send-email-himanshujha199640@gmail.com


Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>