ext4: avoid recheck extent for EXT4_EX_FORCE_CACHE

hulk inclusion
category: bugfix
bugzilla: 109246
CVE: NA
---------------------------

Buffer with verified means that it has been checked before. No need
verify and call set_buffer_verified again.

Signed-off-by: yangerkun <yangerkun@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>