floppy: ignore kernel-only members in FDRAWCMD ioctl input

floppy: ignore kernel-only members in FDRAWCMD ioctl input

Always clear out these floppy_raw_cmd struct members after copying the
entire structure from userspace so that the in-kernel version is always
valid and never left in an interdeterminate state.

Signed-off-by: Matthew Daley <mattd@bugfuzz.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit ef87dbe7614341c2e7bfe8d32fcb7028cc97442c)
[wt: be careful in 2.6.32 we still have the ugly macros everywhere]
Signed-off-by: Willy Tarreau <w@1wt.eu>