fs: cifs: Fix atime update check

Commit 9b9c5bea ("cifs: do not return atime less than mtime") indicates
that in cifs, if atime is less than mtime, some apps will break.
Therefore, it introduce a function to compare this two variables in two
places where atime is updated. If atime is less than mtime, update it to
mtime.

However, the patch was handled incorrectly, resulting in atime and mtime
being exactly equal. A previous commit 69738cfd ("fs: cifs: Fix atime
update check vs mtime") fixed one place and forgot to fix another. Fix it.

Fixes: 9b9c5bea ("cifs: do not return atime less than mtime")
Cc: stable@vger.kernel.org
Signed-off-by: Zizhi Wo <wozizhi@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>