staging/lustre/libcfs: revert changes to libcfs_sock_ioctl

staging/lustre/libcfs: revert changes to libcfs_sock_ioctl

Changes introduced by 80db2734acbc78db12798cfb611d6acc7fe389e6
unfortunately totally break lustre, we use this function
to access not only socket proto obs, but also device ioctl
like SIOCGIFCONF that now fail.
Reverting part of the previous patch to regain the needed
functionality.

Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
CC: Fredrick John Berchmans <fredrickprashanth@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>