Combined setLinkProperties in DataConnection and DataResponse

1. Merged the method setLinkProperties from DataCallResponse into
   the same method in DataConnection.
2. Made gateways field in DataCallResponse final.
3. Moved SetupResult into DataConnection.

This is the preliminary step of moving DataResponse to system API
so it can be part of the data service API, which is required by
IWLAN refactoring.

Test: Telephony sanity tests
bug: 64132030
Merged-In: I434c4f1553954fdda0c58c2eada888d7d6087af4
Change-Id: I434c4f1553954fdda0c58c2eada888d7d6087af4
(cherry picked from commit 86632deb)