em0 dead after suspend/restore on t40

[Randy Bush]

on a t40 running -current, i will often, but not always, see

    em0: Link is up 1000 Mbps Full Duplex
    ...
    em0: The EEPROM Checksum Is Not Valid
    em0: Unable to initialize the hardware
    em0: The EEPROM Checksum Is Not Valid
    em0: Unable to initialize the hardware

on a resume.  after a reboot, 

    em0: <Intel(R) PRO/1000 Network Connection, Version - 1.7.25> \
         port 0x8000-0x803f mem 0xc0200000-0xc020ffff,0xc0220000-0xc023ffff \
         irq 11 at device 1.0 on pci2
    em0: Ethernet address: 00:0d:60:3b:5c:df
    em0:  Speed:N/A  Duplex:N/A
    ...
    em0: Link is up 1000 Mbps Full Duplex

it will work fine.

randy