Document that sx_unlock() exists as a macro. Remove redundant include file, <sys/kernel.h>, and clean up the function list at the top with the addition of a "Sx utility macro" section.
Document that sx_unlock() exists as a macro.
Remove redundant include file, <sys/kernel.h>, and clean up the function
list at the top with the addition of a "Sx utility macro" section.

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