Well, if you don't need it then don't use it ;-) Bus seriously AFAIK, CIFS was not enabled in any kernel in official Nokia firmware. Maybe you flashed custom kernel with CIFS enabled?

As they don't support mounting network shares officially and there is no user friendly interface for it, enabling CIFS would make it a dead weight in kernel taking up precious non-swappable RAM (and CIFS code is quite big, module is >250KB). Nokia did numerous other memory-wise optimizations that save less memory than 250KB so having cifs enabled wouldn't be very clever in that context.