[NET]: allow 32 bit socket ioctl in 64 bit kernel

Since the register_ioctl32_conversion() patch in the kernel is now obsolete,
provide another method to allow 32 bit user space ioctls to reach the kernel.

Signed-off-by: Shaun Pereira <spereira@tusc.com.au>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>