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 int next_valid_format(void)
{
	int probed_format;

	probed_format = DRS->probed_format;
	while (1) {
		if (probed_format >= 8 || !DP->autodetect[probed_format]) {
			DRS->probed_format = 0;
			return 1;
		}
		if (floppy_type[DP->autodetect[probed_format]].sect) {
			DRS->probed_format = probed_format;
			return 0;
		}
		probed_format++;
	}
}

static int next_valid_format(void)
{
	int probed_format;

	probed_format = DRS->probed_format;
	while (1) {
		if (probed_format >= 8 || !DP->autodetect[probed_format]) {
			DRS->probed_format = 0;
			return 1;
		}
		if (floppy_type[DP->autodetect[probed_format]].sect) {
			DRS->probed_format = probed_format;
			return 0;
		}
		probed_format++;
	}
}
