-acpitable {file|data}=file reads the content of file, but it is
in binary form, so the file should be opened usin O_BINARY flag.
On *nix it is a no-op, but on windows and other weird platform
it is really needed.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>