Telephony: Initialize GsmCellLocation class members properly

Default values for class members mLac, mCid, mPsc would be 0.
Initialize these variables with -1 as 0 is considered as valid
value.

Change-Id: I08dc4031bb16293e80e5b7f51afcb8dc11747d3b
CRs-Fixed: 406479
(cherry picked from commit 416e0a2b6983af94245d8aa92d3aa0b1e0ce79aa)
(cherry picked from commit b25e0849cc2449fc95c3091a4599d4f72d2a436b)
(cherry picked from commit 5e48706429f229c8dd54f31a1e19a9a76618f591)