There is no need to hold the freelist lock around alloc/free of software descriptors.  This also silences WITNESS warnings when the software descriptors are allocated with M_WAITOK.
There is no need to hold the freelist lock around alloc/free of
software descriptors.  This also silences WITNESS warnings when
the software descriptors are allocated with M_WAITOK.

MFC after:	1 week

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