MDI interrupt handling

MDI drivers include an intr(D2mdi) entry point routine that handles device interrupts. OThe intr( ) routine handles incoming packets and may initiate transmits on transmit-complete inerrupts. Some Network Interface Controllers (NICs) generate interrupts for other reasons, such as setting a hardware multicast address; the MDI driver's intr( ) routine must be coded to handle any hardware interrupt that the NIC hardware generates.