build: add DEBUG flag to HAL so that TRACE is not silent

Most of the calls in HAL use TRACE to print to stdout/stderr however
the full TRACE is depending on DEBUG flag at compilation.

This is a quick hack, and the whole TRACE system should be re written
with something like:

TRACE_P_FATAL(...)
TRACE_P_ERROR(...)
TRACE_P_WARN(...)
TRACE_P_INFO(...)
TRACE_P_VERBOSE(...)
#ifdef DEBUG
TRACE_P_DEBUG(...)
#endif