drivers/video/amifb.c cleanups

This patch contains the following cleanups:
- make the needlessly global amifb_init() static
- rename cleanup_module() to amifb_exit(),
  make it static __exit,
  use module_exit(),
  there's no need to #ifdef MODULE it

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>