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 const char *drive_name(int type, int drive)
{
	struct floppy_struct *floppy;

	if (type)
		floppy = floppy_type + type;
	else {
		if (UDP->native_format)
			floppy = floppy_type + UDP->native_format;
		else
			return "(null)";
	}
	if (floppy->name)
		return floppy->name;
	else
		return "(null)";
}

static const char *drive_name(int type, int drive)
{
	struct floppy_struct *floppy;

	if (type)
		floppy = floppy_type + type;
	else {
		if (UDP->native_format)
			floppy = floppy_type + UDP->native_format;
		else
			return "(null)";
	}
	if (floppy->name)
		return floppy->name;
	else
		return "(null)";
}
