Fix issue that it would prompt wrong SPN name.

When device boot up, it will prompt a SIM card information,
inclued SPN which is stored by porperty named "gsm.sim.operator.alpha".
But this porperty do not distinguish by phone id.

Save the SPN to porperty distinguished by phone id.

CRs-Fixed: 784555

Change-Id: I0970b00e7156452384093817c1b92dd33ea721cd