LU-17181 misc: don't block reclaim threads

LU-17181 misc: don't block reclaim threads

memory reclaim threads may blocked by lustre reclaim
process, but lustre don't have any benifit from parallel
reclaim.

Test-Parameters: trivial
HPe-bug-id: LUS-11872
Signed-off-by: Alexey Lyashkov <alexey.lyashkov@hpe.com>
Change-Id: I624edbb8833975864706ec51537d2954f5a9cea4
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/52627
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andrew Perepechko <andrew.perepechko@hpe.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>