LU-16609 target: top_trans_create cannot alloc memory

LU-16609 target: top_trans_create cannot alloc memory

top_trans_create() requests __GFP_IO memory allocation,
which does not allow direct reclaim. However, if the
memory shortage is temporary, direct reclaim is reasonable.
GFP_NOFS is __GFP_IO with additional reclaim bits.

Change-Id: I2c84d9d74188660063c948573780745a2b59a688
Signed-off-by: Andrew Perepechko <andrew.perepechko@hpe.com>
HPE-bug-id: LUS-11293
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/50176
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Alexey Lyashkov <alexey.lyashkov@hpe.com>
Reviewed-by: Lai Siyao <lai.siyao@whamcloud.com>