Minimalist gnb tracer to trace (for the moment) rxdataF when some
decoding for PUCCH or PUSCH has been done.

Important: T_BUFFER_MAX and T_CACHE_SIZE have been changed. T_BUFFER_MAX
is twice as big as before. T_CACHE_SIZE has been devided by two. Globally,
the memory usage of the T tracer is the same, but since we divided by two
the number of buffers in the cache, we may hit some realtime problems if
all the buffers are busy at some point. The simple solution would be to
use 8192*2 for T_CACHE_SIZE as it was, but then we double the memory usage
of the T tracer. This, or another solution, to be defined.