quota: avoid increasing DQST_LOOKUPS when iterating over dirty/inuse list

mainline inclusion
from mainline-v5.5-rc1
commit 05848db2
category: bugfix
bugzilla: 188812,https://gitee.com/openeuler/kernel/issues/I7E0YR
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=05848db2083d4f232e84e385845dcd98d5c511b2

--------------------------------

It is meaningless to increase DQST_LOOKUPS number while iterating
over dirty/inuse list, so just avoid it.

Link: https://lore.kernel.org/r/20190926083408.4269-1-cgxu519@zoho.com.cn


Signed-off-by: Chengguang Xu <cgxu519@zoho.com.cn>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Yang Erkun <yangerkun@huawei.com>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>