floppy: remove register keyword use from floppy driver

The floppy drive is slow.  These days I see absolutely no good reason why the
floppy driver should try to gain a tiny bit of speed by telling gcc to
optimize access to some variables via the register keyword.  Better to just
leave gcc free to do whatever optimizations it deduces to be sane and not
hamper it by telling it that some variables in the floppy driver are special
and need to be fast (they don't).

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>