Properly implement bus_setup_intr so that it handles the configuration of interrupts of direct children. Have the bus_config_intr and bus_teardown_intr methods implemented by bus_generic_config_intr and bus_generic_teardown_intr (resp) as we don't need to do anything special outselves.
Properly implement bus_setup_intr so that it handles the configuration
of interrupts of direct children. Have the bus_config_intr and
bus_teardown_intr methods implemented by bus_generic_config_intr and
bus_generic_teardown_intr (resp) as we don't need to do anything
special outselves.

This removes all the ``#ifdef $arch'' code that was there because powerpc
didn't have a proper nexus and people tend to copy and paste stuff.

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