MFC: Fix some of the hangs reported with the real mode BTX by disabling interrupts for software interrupts.
MFC: Fix some of the hangs reported with the real mode BTX by disabling
interrupts for software interrupts.

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