hal/*/*/ml605/mem_layout.h: add ACQ SMIO hard limit

As of now, we don't have a way of checking which
channel is tha valid one. So, we hardcode this limit
in software, for now.

This is a quick fix for github issue #21.
hal/sm_io/modules/acq/*: add channel limit checking

This finishes the quick fix for github issue #21.
examples/acq.c: add better limits checking

A few hard limits were imposed to avoid segmentation
faults due to very large integers.