Redirect getNeighboringCellInfo to CellInfo

Call getAllCellInfo instead of getNeighboringCellInfo
internally, to stop using the NeighboringCell HAL.
This will allow us to consolidate these API calls to
the modem into a single path, and enable us to remove
support for NeighboringCellInfo in a future release.

Bug: 62490173
Test: manually tested with SL4A using both P and P+
    target SDKs.

Change-Id: Ic8d2f65401785e7435601c0f4d3e432b07d218be