Off by one in floppy.c

Another coverity patch i forgot to resend, original thread here
http://marc.info/?l=linux-kernel&m=115144559823592&w=2

In case drive == N_DRIVE, we get one past the drive_params array.

Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>