Add the user set network mode to the siminfo table

* To track what the user set for the particular sub independent
  of the currently set network mode (i.e. PREFERRED_NETWORK_MODE)
* Useful on MSIM where the modem may only support 2G on one of the slots,
  so the preferred network mode (and the NETWORK_MODE column) would
  not always reflect the user desired network mode.

Ref: CYNGNOS-291

Change-Id: Ic6cc66d3dc2277f920785679c7fcc6e3c7581570