LU-9464 hsm: use OBD_ALLOC_LARGE() for hsm_scan_data array

LU-9464 hsm: use OBD_ALLOC_LARGE() for hsm_scan_data array

In mdt_coordinator() use OBD_ALLOC_LARGE() rather than OBD_ALLOC() for
the hsm_scan_data request array.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: Ieb648dfb92e6019ab316c7643aa0c0b5cf1d86f7
Reviewed-on: https://review.whamcloud.com/27014
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Li Xi <lixi@ddn.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>