Update comment to prefer M_NOWAIT over M_DONTWAIT and M_WAITOK over M_WAIT.
Update comment to prefer M_NOWAIT over M_DONTWAIT and
M_WAITOK over M_WAIT.

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