In 2375, usx2y ALSA driver was deactivated. However the way it was
done causes driver->hw to stay NULL and then referenced. This causes
SIGSEGV, as described in #95 description.
git-svn-id: http://subversion.jackaudio.org/jack/jack2/trunk/jackmp@3036 0c269be4-1314-0410-8aa9-9f06e86f4224