Fix 'get counters STREAM_INPUT idx'
Fix 'get counters STREAM_INPUT idx'

Fix indexes for STREAM_INPUT_FRAMES_RX and STREAM_INPUT_FRAMES_TX
in stream_input_descriptor_imp::get_counter_by_name().

andrew-elder/avdecc-lib,audioscience/avdecc-lib,audioscience/avdecc-lib,audioscience/avdecc-lib,andrew-elder/avdecc-lib,andrew-elder/avdecc-lib