staging: lustre: Use __user for a pointer to a user space address

This commit corrects two sparse warnings caused by the lack of a __user
annotation for the third argument of the libcfs_ioctl_handle function.

  module.c:165:68: warning: incorrect type in argument 1
    (different address spaces)
  module.c:165:68:    expected void [noderef] <asn:1>*arg
  module.c:165:68:    got void *arg
  module.c:209:47: warning: incorrect type in argument 3
    (different address spaces)
  module.c:209:47:    expected void *arg
  module.c:209:47:    got void [noderef] <asn:1>*arg

The need to have the __user annotation is supported by the fact that
libcfs_ioctl_handle passes its third argument to a helper function
(libcfs_ioctl_popdata) which also has a __user annotation for its
corresponding argument.
Signed-off-by: M. Vefa Bicakci <m.v.b@runbox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/libcfs/module.c

@@ -116,7 +116,7 @@ int libcfs_deregister_ioctl(struct libcfs_ioctl_handler *hand)
 EXPORT_SYMBOL(libcfs_deregister_ioctl);
 
 static int libcfs_ioctl_handle(struct cfs_psdev_file *pfile, unsigned long cmd,
-			       void *arg, struct libcfs_ioctl_hdr *hdr)
+			       void __user *arg, struct libcfs_ioctl_hdr *hdr)
 {
 	struct libcfs_ioctl_data *data = NULL;
 	int err = -EINVAL;