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 struct kobject *floppy_find(dev_t dev, int *part, void *data)
{
	int drive = (*part & 3) | ((*part & 0x80) >> 5);
	if (drive >= N_DRIVE || !floppy_available(drive))
		return NULL;
	if (((*part >> 2) & 0x1f) >= ARRAY_SIZE(floppy_type))
		return NULL;
	*part = 0;
	return get_disk(disks[drive]);
}

static struct kobject *floppy_find(dev_t dev, int *part, void *data)
{
	int drive = (*part & 3) | ((*part & 0x80) >> 5);
	if (drive >= N_DRIVE || !floppy_available(drive))
		return NULL;
	if (((*part >> 2) & 0x1f) >= ARRAY_SIZE(floppy_type))
		return NULL;
	*part = 0;
	return get_disk(disks[drive]);
}
