Return early in printreg() when the pointer is NULL.  For FreeBSD, the strings describing the drive status and error bits are so deficient that the pointer is always NULL.
Return early in printreg() when the pointer is NULL.  For FreeBSD, the
strings describing the drive status and error bits are so deficient
that the pointer is always NULL.

Reported by:	Philippe Charnier <charnier@lirmm.fr>

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase