quota: fix condition for resetting time limit in do_set_dqblk()

We reset time limit when current usage is smaller
or equal to soft limit in other place, so follow
this rule in do_set_dqblk().

Signed-off-by: Chengguang Xu <cgxu519@zoho.com.cn>
Link: https://lore.kernel.org/r/20190724053216.19392-1-cgxu519@zoho.com.cn


Signed-off-by: Jan Kara <jack@suse.cz>