LU-7623 lmv: Mark lmv_hsm_ct_register/unregister uarg as __user

LU-7623 lmv: Mark lmv_hsm_ct_register/unregister uarg as __user

Since it is a userspace pointer, this makes things neater and
sparse happier.

Change-Id: I3249ecba20a2018b6ebba4d257ce918b4bd9aed1
Signed-off-by: Oleg Drokin <oleg.drokin@intel.com>
Reviewed-on: http://review.whamcloud.com/17783
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>