LU-9983 osp: align the OSP request size by 4k

LU-9983 osp: align the OSP request size by 4k

In osp_object_update_request_create() round up the size of the object
update request to a multiple of the PAGE_SIZE to avoid issues with IB
HW that cannot handle gaps in memory regions.

Signed-off-by: Di Wang <di.wang@intel.com>
Change-Id: Id5c16b031dcb16d764c4e4f325f51b9ecf454533
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-on: https://review.whamcloud.com/29270
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>