MTD is now always build with partitioning support so this can be
removed.

Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>