DecodeTxTimer wraparound with longTimer == true

[therealergo]

If DecodeTxTimer in lcs_node.c is called with longTimer == true, then for values of txTimerIn exceeding 7 the returned value will exceed the range of a uint16_t type and produce unexpected results.

Returned values from DecodeTxTimer with txTimerIn in the valid range [0...15] are:
4096
6144
8192
12288
16384
24576
32768
49152
0
32768
0
0
0
0
0
0

I do not have a copy of the referenced "Tech Device Data Rev 1 p.9-17" (if there is a copy available please let me know!) but I suspect that this behavior is not intended.