hm2 test: plenty of room in dmesg for debug messages now

Hardy's RTAI kernel had a severely limited dmesg buffer, but that's
behind us now.

Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>
hm2 test: don't violate strict aliasing rules

Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>