Expose CellInfoTdscdma

Expose CellInfoTdscdma and CellSignalStrengthTdscdma
which are both returned by existing public APIs.
This corrects an oversight whereby the values returned
by the public API could not be used by callers.

Existing CTS tests already validate these structures as
though they were public (which was the intention).

Note, this was also requested as feedback in the public
beta.

Bug: 128880490
Test: cts - atest CellInfoTest; atest SignalStrengthTest
Change-Id: Ia75ea9af52796729e26b85ca04fd97b6c9b80f8e
(cherry picked from commit b2bfb295)