scsi: sg: sg_ioctl(): fix copyout handling

First of all, __put_user() can fail with access_ok() succeeding.  And
access_ok() + __copy_to_user() is spelled copy_to_user()...

__put_user() *can* fail with access_ok() succeeding...

Link: https://lore.kernel.org/r/20191017193925.25539-1-viro@ZenIV.linux.org.uk


Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>