Keyguard:Save the sim states based on slotId instead of subId

The sim state broadcast may be received with dummy
subId(until the IccId reading is complete, after which valid subId
is available for the slotId) for a particular slotId. Currently
the KeygardUpdateMonitor saves the sim states based on the subIds.
For a particular slotId, saving the sim states based on dummy/invalid
subIds as well as the valid subIds causes inconsistent behavior and
undesirable effects.

Save the sim states in the KeyguardUpdateMonitor based on the
slotIds.

Change-Id: I02c718fa39ce4ed06c817347c526d49073114e30
CRs-Fixed: 772949