Add some PCI-X register definitions.
Add some PCI-X register definitions.

PCIM_CMD_SERREN -> PCIM_CMD_SERRESPEN to be consistent with
the PERR definition.

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