LU-9683 ptlrpc: fix argument misorder

LU-9683 ptlrpc: fix argument misorder

involved in timediffs calculation.

Change-Id: Ib4a45dddb3866824b696aaeaa190f2ab9b1c71ac
Signed-off-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-on: https://review.whamcloud.com/28027
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Niu Yawei <yawei.niu@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>