staging: lustre: libcfs: add lock-class for cfs_percpt_lock

staging: lustre: libcfs: add lock-class for cfs_percpt_lock

initialise lock-class for each sublock of cfs_percpt_lock
to eliminate false alarm ""possible recursive locking detected"

Signed-off-by: Liang Zhen <liang.zhen@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6432
Reviewed-on: http://review.whamcloud.com/14368
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>