This converts the amifloppy driver to pass the timer pointer to the
callback instead of the drive number (and flags). It eliminates the
decusagecounter flag, as it was unused, and drops the ininterrupt flag
which appeared to be a needless optimization. The drive can then be
calculated from the offset of the timer in the drive timer array.

Additionally moves to a static data variable instead of the
soon-to-be-gone timer->data field.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Krzysztof Halasa <khc@pm.waw.pl>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>