opensimpad: MMC support + better support for SinusPad and 128M SIMpad

opensimpad: MMC support + better support for SinusPad and 128M SIMpad
- There's now a config options to build the kernel for 128Mb SIMpad
  (as there was one for the SinusPad)
- The .bb files automatically turn on these options depending on the
  total memory available.
- The MMC driver was made by Clement Ballabriga <clement@asso.ups-tlse.fr>
  and Guylhem Aznar <simpad@externe.net>.
  Adding an MMC card (internal or external) to the SIMpad is described
  on these pages:
  http://externe.net/zaurus/simpad-bluetooth/
  http://www.iral.com/~albertr/linux/simpad/mmc/