floppy: don't write kernel-only members to FDRAWCMD ioctl output

Do not leak kernel-only floppy_raw_cmd structure members to userspace.
This includes the linked-list pointer and the pointer to the allocated
DMA space.

Signed-off-by: Matthew Daley <mattd@bugfuzz.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
static void schedule_bh(void (*handler)(void))
{
	WARN_ON(work_pending(&floppy_work));

	floppy_work_fn = handler;
	queue_work(floppy_wq, &floppy_work);
}

static void schedule_bh(void (*handler)(void))
{
	WARN_ON(work_pending(&floppy_work));

	floppy_work_fn = handler;
	queue_work(floppy_wq, &floppy_work);
}
