ovl: do not fail because of O_NOATIME

ovl: do not fail because of O_NOATIME

In case the file cannot be opened with O_NOATIME because of lack of
capabilities, then clear O_NOATIME instead of failing.

Remove WARN_ON(), since it would now trigger if O_NOATIME was cleared.
Noticed by Amir Goldstein.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
[sw0312.kim: backport v5.11 mainline commit b6650dab404c to resolve overlayfs file open EPERM fail issue in v5.10]
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Change-Id: I9c0c74747bb4a208fc68ca561f740281b2b553fe