mtd: OneNAND: add support for OneNAND manufactured by Numonyx

In addition to adding the Numonyx manufacturer code, this patch
also ensures 'sync. write' is disabled when reading identification
data - something that the Numonyx chip objects to, but the
Samsung chip seems to ignore.

Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>