m68k: Atari fb revival

Update the atari fb to 2.6 by Michael Schmitz,
Reformatting and rewrite of bit plane functions by Roman Zippel,
A few more fixes by Geert Uytterhoeven.

Signed-off-by: Michael Schmitz <schmitz@debian.org>
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>