Remove an unused syscallarg() macro leftover from this code's origins in NetBSD.
Remove an unused syscallarg() macro leftover from this code's origins in
NetBSD.

Approved by:	re (scottl)

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