LU-18024 quota: fix the order of freeing qmt_lvbo_free_wq

LU-18024 quota: fix the order of freeing qmt_lvbo_free_wq

In qmt_device_fini, put the freeing of the qmt_lvbo_free_wq after
all possible usage of it having finished cleanup.

Signed-off-by: Hongchao Zhang <hongchao@whamcloud.com>
Change-Id: Ia26f1bc490adff5ae7dc850e2c89baf5874f01c5
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56778
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Sergey Cheremencev <scherementsev@ddn.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>