This commit adds basic support for the Litecell 1.5. Multi-TRX is not
supported yet. Instead, multiple instances of the BTS can be launched
using command line parameter -n <HW_TRX_NR> to specify if TRX 1 or
2 must be used by the bts. Note that only TRX 1 opens a connection to
the PCU. Full support for GPRS on both TRX will come at the same time
than the multi-TRX support.
The BTS manager has been adapted to match the new hardware but otherwise
it has not been improved or changed compared to the one used on the