Freeze networkstack-aidl-interfaces to version 12.

This AIDL freeze includes two new Integer ipv4ProvisioningMode
and ipv6ProvisioningMode to represent different provisioning mode
in ProvisioningConfigurationParcelable.

Bug: 161838070
Test: NetworkStackIntegrationTest NetworkStackTests
Test: verify wifi works on latest aosp master and R.
Change-Id: I0932505e408697dafe0ba89855b878dc1c2e9878