IXP425: split handling of the two QMGR interrupts so they are separately managed. Adjust ixpqmgr_{attach,detach} to comply with device_* interface.
IXP425: split handling of the two QMGR interrupts so they are separately
managed. Adjust ixpqmgr_{attach,detach} to comply with device_* interface.

Reviewed by:	cognet, imp, sam, stass
Tested by:	cognet

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