Telephony: Call forwarding icon is shown after powerup.

If call forwarding was enabled, then the call forwarding
icon should be shown after the phone has powered down and
powered-up irrespective of SIM having EfCfis and EfCff.
Added a preference parameter to store the call forwarding
status, in case it's not updated correctly by the network
operator.

CRs-Fixed: 275722 795137 806156
Change-Id: I616d2e73fd75a58fc1628bedb34126b00d31cba1