Initialize RIL with the correct CDMA subscription mode setting

Users choice of CDMA Subscription Source is stored in CDMA_SUBSCRIPTION_MODE
setting in database.
If telephony restarts after a crash, PhoneFactory sets the
CDMA subscription source value from PREFERRED_CDMA_SUBSCRIPTION
setting and that causes the mismatch with the value in the settings
database chosen by the user. The change is to use the
CDMA_SUBSCRIPTION_MODE setting instead when creating the RIL object.

Also, remove the Setting PREFERRED_CDMA_SUBSCRIPTION from the database.
With this change the special treatment for LTE on CDMA will not be needed.
The correct value can be set in the database for CDMA_SUBSCRIPTION_MODE
and that will be taken on power-up by this code.

Change-Id: I11fff596a5fe721c64f192c889672326517dc43d