mce-test: Add file attributes to open

This fixes a compile warning.

open(2) manpage says:
... mode specifies the permissions to use in case a new
file is created. This argument must be  supplied  when
O_CREAT is specified  in  flags; ...

Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Chen Gong <gong.chen@linux.intel.com>
1 file changed