Add TimeStamp Constructor for HAL 1.4 Support

Becuase the Timestamp is no longer passed by the
radio, CellInfo objects are stamped when received
by the RIL. Since the structure passed to these
constructors is a HAL structure, we have to pass the
timestamp all the way through to have it supported
for constructors invoked on a 1.4 HAL object.

Bug: 126911026
Test: atest RILTest#testCellInfoTimestamp_1_4;
      atest RILTest#testCellInfoTimestamp_1_2
Change-Id: I2b0833a0a8b6eeb75bff9cbe956ad36656a46208