Disable use of O_TMPFILE by default

It is not uncommon for embedded devices to use
relatively older versions of the Linux kernel,
where file systems do not support O_TMPFILE
(since Linux 3.11) or implementations contain
bugs (with fixes available in some > 3.11 version).

Change-Id: Ic204bf6dcbdbcece87d42eea8eed9e114bd757ad
Reviewed-by: Teemu Holappa <teemu.holappa@theqtcompany.com>